good question – I'm no expert, but basically if you HODL you're fine. If you're looking to make short-term trades for EUR fiat, you'll be subject to a pretty high captial gains.

A lot of the "crypto" firms here (BitPanda, etc.) have tax services they offer as well if you're a trader.

But if you just hold sats and use them occasionally....

https://koinly.io/guides/crypto-tax-austria/

also ITM from Sir Non-Hipster Man Beard of Gitmo Nation Wiener Schnitzel