What are some good exchanges allowing fixed monthly investment in BItcoin? I need options where my funds will be secure.
Why are you looking for exchanges, buddy? It seems you got some air-droppedd merits, which means you are here for awhile, but didn't you read any threads where authors warned readers that you should not keep your money on online accounts? Theymos has wrote a thread with this title. Yet you are searching for an exchange to invest.
I have seen atomic wallet where you could stake your crypto's (Not Bitcoin) and make some money. But since the last hack of Atomic wallet, I do not trust them anymore. So, I recommend not to use any kind of centralized exchanges to stake your money.