I believe the future is for BTC and my investments will be mostly in it. I wanna use Electrum as my main BTC assets store. As I heard exchanges are not safe for storing purposes.
You made the right decision dear, I did not mention the usage of Electrum for holding purposes in my reply to your previous post but it's a good choice because it is open source and it can be used with Hardware wallets as well of course it has many other features too. But the most you should see is that the wallet is open source and non-custodial if it has both properties then you can prefer it over custodial wallets like CEXs.
Also my plan is to invest after that litle by litle for example from my income to invest 100-200$ in month.
In your previous post, you did not mention that you are planning to invest in part, as you only mentioned you have capital of $1500 so what would be better for you, well if you said, you are a job holder and have a monthly income then I will definitely suggest you to go for DCA as buying in little will not become a weight on your pocket as you only have to invest with what your life will not be disturbed.
I am glad that you are making progress.