OK so if I but the coins on Bisq. Or Batstamp and then store them in the Electrum wallet, is it easy to do  that?

Apologies for all the noobie questions, I just wanna do this right, thanks everyone

I was using the blockchain
.info website and linked with the mobile app, they asked for passport Id verification,

Can I buy my bitcoin through the electrum wallet, I have also ordered a Nano Ledger S online which I should have in the next few days

As the title says, also... Is Blockchain a reliable way to buy and store Bitcoin

Is there anything better that people would recommend

I am looking for advice here, If Bitcoin goesets day to $1M dollars, let's talk hypothetically, how will you be able to sell it, who is going to buy it off you at that price, will you not be stuck with it?
Even if it goes to 100k a coin how would I out possibly sell it?