The transaction fees are based on the transaction sixe and how congreted the network is but t shouldn't cost you more than a  couple of dollars to send from your soft wallet to hardware wallet.

If you have 1 BTC, you'll always have 1 BTC whether that's stored in an exchange or a hardware wallet. It's the USD value goes up and down, but no, just because you see the USD vslue going down in your hardware wallet does not mean that the funds can be accessed by a hacker. Your hardware wallet software just use exchanges to request the Bitcoin price based on your holdings. Doesn't affect the safety of the funds.

OmegaStarScream is right. The value of your bitcoin in dollars would increase or decrease anywhere you store your bitcoin, either in an exchange or in your self custody wallet. As for the fee, it's when the blockchain is congested they you can pay high, but if it's not congested, it's just something little that you pay. You can use https://mempool.space/ to check out the transaction fee of the amount that you want to send for adjustment.

Also I have done few transactions with bybit and few of my Indian friends told me to buy crypto from binance, so is binance legal in India? Few says illegal some says legal, I don't know in exact about legalisation in fact I have zero knowledge about technical and what I planned is to buy bitcoin from binance, bybit and store in trezor wallet only. Any Indian sir/Mam here? Thank you again

What you hold in your hard wallet and on an exchange is the same Bitcoin, so it has the same value. The difference lies in where you choose to store and secure it. You can use a hardware wallet, an exchange, or a software wallet. However, the safest option is a hardware wallet because you have full control over it.

Do more research man, you need to understand the basics of Bitcoin and how to secure it properly. Since it’s your investment, you definitely don’t want to lose it due to a simple mistake. Take the time to protect it!

Many newbies makes the mistake of thinking that their BTC is stored in their wallet, not knowing that the wallet is the access to their coins on the Blockchain. Some will also panic when they see their Bitcoin reducing in USD value, not knowing that it's because Bitcoin is volatile and it's price can pump or dump. Adequate knowledge of how Bitcoin works is very necessary for newbies that wants to start holding it so that they will not worry unnecessarily when they notice any changes in price. Knowing that if your BTC is in a none custodial wallet, that makes you to be in total control, if you lose your wallet keys you lose the access to your BTC on the Blockchain.

Check this article[1], it says that Binance is back in india after its ban on January last year. And if you can access Binance using your local ISP the  you're good to go. I suggest and preferred P2P to buy as is much cheaper to buy bitcoin. It just needs KYC, and read/follow all the notes and warnings shows in the P2P page for your own safety.

[1] https://www.binance.com/en/square/post/12198392258345

One Bitcoin will remain at the same market value whether you keep it on a trading platform, in your own wallet, or even in a casino.

The transfer fees will not exceed a few dollars, and perhaps even less than that. This is if we are talking about fees on the network. However, if you are going to transfer Bitcoin from a trading platform to your own wallet, the fees will be a little high because the platform imposes additional fees for its services, and Bitcoin withdrawals are always expensive.

Your question confirms that you are still a beginner in this space and it will be somewhat risky to invest in a way that you do not master. This will make you vulnerable to hacking or manipulation by any party that may use it. I advise you to spend more time learning the basics of crypto and I suggest that you focus on Bitcoin and its protocol because it will make it easier for you to understand the mechanisms of the rest of the networks