Most card only shops/places have a sticker on there door. But as a non Dutch person you probably don't know how they look.
If you are somewhere where card or cash is not always accepted it's pretty normal to ask beforehand. Past summer we where on holiday in the Balkan where paying with card wasn't always possible. We just ask beforehand then we can check if we had enough cash or we choice to go somewhere else.
If you in a situation (especially in a bar) there is probably someone how is willing to pay for you with card and you pay them with cash. You maybe don't get all the change but you problem is fixed. Or how it was fixed now.
But if you are abroad and don't know it just ask beforehand. Doesn't matter if you want to pay with card or cash.
I use a quest 1 on Linux.(According to the alvr the quest 3 is also fully supported) Played about the last half of half life on Linux.
However some VR games just don't run well under proton I still have windows installed for that. Even if i didn't boot into windows for a half year now.
Also first recommend installing Linux in dual boot with windows if you don't know if al your programs/games work. Nowadays most stuff works but you can always keep windows for just in case.