Welcome back! And sorry to hear about that. I am going to assume you want some kind of certainty/security first. If so, I would get a hard wallet like Trezor or Ledger to have your own keys. After that, I guess exchange is personal preference but I use them all. Binanceus has the lowest fees for me. But I use Coinbase to buy other coins like dot. Voyager is pretty good too just make sure the coin ur buying can be withdrawn to a wallet. As for mining, maybe a small asic like the goldshell boxes or a gpu rig. Some people run those on a separate network and I recommend hiveos. Just my 2 cents, good luck out there!