You know that could be the start of bear market. I will not advise anyone to buy huge amount of bitcoin around that time but to just buy little amount of it. Use like 90% to buy USD and start DCA. Using the fiat to buy bitcoin as the price of bitcoin is decreasing. It is better like that than to just convert all to bitcoin at once.

So you can wait from now till 2026 before investing on bitcoin, maybe before then all your assets on other altcoins could have vanished away on losses and you may not be left with any profit again to use in making bitcoin investment, why not do that now, take the profits and invest in bitcoin, we are still on the post halving market pump, which means if you can buy now, you have higher chances of making profits till we reach to a new all time high of above $100,000 and by the year 2026, you could have achieved what you're meant to started with already.

Well, its still up to you. If you want to focus on bitcoin and accumulate a huge portion of bitcoin in preparations for the next bull run or big events in bitcoin, then I guess it's better to convert your altcoins into bitcoin, but not all because the fact that you are investing in altcoin means you are earning in more than one currency. So for me, it's better to convert just some of your altcoins into bitcoin so that you can still earn through your altcoin assets. 
 
But if you feel that a certain altcoin is not going to last or is not profitable, then that's the time that you will need to convert your altcoin to bitcoin and focus on it. It's not bad to hold altcoins; it's just that not all altcoins can be trusted and have the potential to give profit to investors, so the safest and most tested currency is bitcoin. You just need some patience because in order to earn huge amounts, you will need to do so.

You can actually start accumulating your Bitcoin now instead of waiting till the next Bull run in 2026 which I doubt because it's not certain, don't forget that those altcoins are not reliable, however I still don't see the reason to delay till 2026, so i would advise you invest all your profit into Bitcoin, you can use the DSA method to help you start accumulation no matter the price, wether high or low.
If you can HODL till 2030 then, it's obvious your a long time holder, which I think will help you get your return in investment.

You have a good plan but the problem is your ability to know the peak of the bull run. Waiting for the next six months to one year to start selling your coin is a good prediction but it will be better to have a price that the coins will get to and you sell. Instead of waiting for the peak of the bull run just have a price benchmark. You might also face the same challenge of knowing when to buy. I suggest you keep your funds after selling the altcoins and consider using DCA gradually. Buying Bitcoin adopting a lump sum strategy might not be appropriate for a newbie. I also appreciate your long-term investment plan. All things being equal, you will surely profit after these years of hodling.     

Just for myself setting up a pattern that may not be good for others. Not suggesting anyone to do so.
For me it's still in an uptrend which is still good to hold until a new ATH price is expected to happen based on the four year cycle.
Now. If you have Bitcoin in your wallet and some potential altcoins but still not enough, buy more consistently before Bitcoin reaches $80k. When it reaches the top, sell and hold USDT in preparation for buying when the trend goes down.

If you feel that the price is still high when you take profit from your altcoins, why not just convert it first into USDT or stable coins then buy Bitcoin when you think that it is already low.
It is also possible that those who advise you to just swap your altcoin profit straight to Bitcoin, are aiming for a long term HODL that is why they don't really care much about the price right now, since they believe that it would be worth it in the long run.

As a forum bitcointalk, you should be ashamed of not having bitcoin until now!

It's sad that you started with altcoins, and not with the first cryptocurrency.

An ideal plan (to maximize accumulated bitcoin) should look something like this:
sell altcoins at the maximum price during a bull run -> convert into stablecoins -> buy bitcoin at the minimum price during a bear market.

The problem is that at every stage something can go wrong.

Any advice should be treated with caution, and even more so, do not follow what is said literally. Tailor any advice to suit your needs.

Impossible to say. Best just to avoid altcoins in general. Not sure why you only have alts and no bitcoin. Guessing you jumped into the market without really knowing what you were doing.

There's no way to know when your specific altcoins will go up or down. They could peak well before bitcoin peaks, Altcoins are fads so there is no way to know if the specific altcoins you have will be the "in" fad at the time when bitcoin is peaking, or if they'll peak well before that, or even not peak until after the bear market starts.

Only best advice anyone can give you is to get out of alts and get into Bitcoin and hold Bitcoin long term. It's entirely up to you to decide when you get out of that cr*p and move into Bitcoin.

Also know way to know where Bitcoin bottoms next bear market. I think it'll probably bottom in the $60,000s, but maybe it'll go all the way down to $40,000s or $50,000s, maybe it won't drop below $80k. Nobody can tell you.

If people are telling you to convert right now to Bitcoin, they are simply advising the safest thing, because the sooner you are out of alts and into Bitcoin the safer your money is. If you don't sell until late in the bull market then yeah it will probably turn out better for you to wait for a crash after the bull market ends, but nobody can tell you when or at what price to buy back. Nobody can tell you when the best time to sell your alts or to buy back into bitcoin is. But when talking about moving from risky short term fads to the best currency humanity has ever had (which also happens to be the most successful public investment in human history), the sooner the better is a decent strategy.

Hmm, bro, there's nothing wrong with your mindset but I would like to give some advice from my experience that this is not the market cycle like previous ones,  so in order to secure some decent buying iw would like to advise you should accumulate some of the amounts in this bull rally as well because in the dips we get some decent opportunities. Maybe after this bull runs you won't be able to make proper accumulations, due to high market value.

Yup, there's nothing wrong in converting some of the profits from the other assets to Bitcoin as this can be a decent strategy to accumulate the required amount to hit your goal. By the way, you should hold cash as well in order to take advantage of the market volatility.