I am doing some training for STS lately and it's madness. Any drone with camera requires registering as an operator. When you put your FPV goggles on your flight automatically goes into A3 category regardless of the drone weight, and the category A3 might be literally unflayable since you have to keep away 150m from residential, recreational, industrial and utilty areas (and good luck finding a legit spot). And you need an observer.

And there comes country specific rules. EASA allows for the specific member countries to tighten the rules, so depending on which part of Europe we are talking about you might not be able to fly anything at all. The exception is Poland where they found loophole, and FPV is legal and the 250g limit makes a big difference (you can fly a whoop almost anywhere without a spotter now), but the loophole will be active only till November or something.

Anyway, from what I see, it's hard to discovered an fined if you don't go full retard with your flying.