I suggest hitting up google or ChatGPT to have a comprehensive understanding of what checks happen at an airport, but basically, the "can I bring X pill / Y plant seeds / whatnot into the country" kind of questions are handled at customs, at the absolute end of the whole process, when you already entered the country.

And, here's the thing. Customs look really lax compared to all the other checks, at least in some airports, but certainly in Budapest. No queues per se, more often than not they don't even care about you and so on. That's because the customs check is intelligence driven, modern customs uses data and profiling to assess risk.

And it can literally look so lax that literally nobody will be there.

This is of course in stark contrast with immigrations check (where your passport is checked), which is impossible to avoid and is mandatory. Basically, your plane lands, you will be somehow escorted to immigrations, you go through it, pick up your baggage, then breeze through customs. And that last part can literally be a breeze - just walking through a corridor without anyone bothering you.