To clarify regarding a Qt wallet -- I worked on one for a while back in 2017 (in free time) made to work against version3, but it wasn't quite (open source) release ready, let alone 'production' ready. Aside from some UI issues, some sprawling console debug messages and needing better error handling, I recall thinking it was close, supporting either mainnet or testnet (and setup to default against the community servers as the backend). I was able to do deposits and sends using mainnet across multiple BIP44 accounts w/o issue, though I don't recommend anyone do that without review and testing, etc. I got it building recently, but I'll have to clean it up a bit before posting somewhere. Happy to have some more eyes on it though, in case some of it is useful to anyone. It wasn't the first stab at writing a wallet, so I think it benefits at least a little from past attempts.