Okay I got an anon zap, so I'll take it. Few things. Vienna, overall, doesn't have the same level of merchant adoption you'll see in Prague or even Munich, but there are a few places. Check out @Das Delicious. Bitcoin-Restaurant here, as well as a few Latin American cafes and restaurants on @BTC Map

BTC Map

Easily find places to spend sats anywhere on the planet.

Austrian capital gains tax is insanely high (27.5%) for any BTC bought after 2021. If you use any of the major exchanges based in Austria (Coinfinity, Bitpanda) they'll automatically collect this tax if you sell through there. When it comes to MiCA, most of the Austrian-based firms have already committed to following this, and already do tons of KYC, so I don't think this will change much. If you mean "living" on BTC, likely the best way would be to use platforms like @Bringin | The Complete ₿itcoin App or @Bitrefill which you probably know. These platforms do use KYC, so you'll have to submit an identity document and could be on the hook for taxes if your tax residency is Austria. But for spending sats and their debit cards (or gift cards) the solutions they have are pretty good.

Bringin

For the few merchants I personally use that are usually small companies (barber, butcher, etc.) I've been moderately successful at getting them to accept Bitcoin, but nothing super official. Obviously, the meetup community is great here, either Bitcoin Austria or Einundzwangzig Wien. I regret that I'm not able to join more usually because I'm traveling. Hope this helps and happy to answer any other questions!