I think the only important question on your list of questions is how to know the right time to invest in bitcoin, the rest of other questions are completely unnecessary - sorry to say.

And in terms of knowing the right time to invest in bitcoin, I will say the same thing I've always said when I come across questions like this, and that is that, there is no right or wrong time to invest in bitcoin as long as we are already here today looking forward to tomorrow., the only right time I can say - to invest in bitcoin was yesterday, but since yesterday is past and no way to go back into it, another right time is today and now, and this is because, in terms of price, the market movement is unpredictable, you might want to for price to drop but instead, it end up going up.

So for me, I think the best time to invest in bitcoin in exactly the time you have your funds ready, and have made up your mind in invest that funds in bitcoin, you may decide to use DCA or any other strategy, but what is most important is that, you have taken the decision and are already investing.

As I am seeing that you have mentioned that you are beginners and I think you are under the misconception that short-term trading is for beginners and long-term trading is for experienced traders. The correct thing is that short term trading is for professional well analysis skilled traders and on the other hand Long-term trading can be done by beginners to professional level traders. Because short term trading requires more analysis than long term trading. On the other hand, long-term trading is done by following a simple DCA method and starting investment for long-term, in this case you just have to adopt an affordable amount of bitcoin after a certain period like every week or month.
If you invest in Bitcoin in the long term, you don't need to spend much time for analysis, so I don't think that investment in Bitcoin will have any effect on the business.
Your stable income and a certain percentage of which you can afford to invest in Bitcoin