Thanks again for those answers.
I don't think i should transfer my coins to electrum yet. It seems like many (or even all) big online wallets/brokers are saturated right now, and i see a lot of people complaining about very slow money transfers (or even ""stolen"" money!!).
I think i'm going to buy my btc and alts from CEX.IO. Is that a reliable site? I definitely won't use Kraken indeed.
You can buy anytime some btc on an legit exchange but the thing here is that you should let those btc idle on your exchange wallet it would really be risky since you dont have the private key of that unlike if you do use electrum it would be on other way you might charge some big fees but for me it would really be worth of than on losing it all or you dont have a confidence on storing it in on exchange wallet theyre really entire different.