I've never had any trouble buying crypto on coinbase. But I wouldn't keep it there when you start to get a healthy portion of funds.
Then you should move it to cold storage. Tangem is pretty cool (use DJC36L to get 10% off)
For which crypto to buy I wouldn't feel safe to reccomend anything else than btc. Eth and Sol looks like they could keep growing at the moment but who knows..
