GH / FH are certainly big, but well worth it.
The scenario environments are made of 2-5 boards that link together (like huge jigsaw puzzle pieces) There are a lot of different boards - maybe 40 or so - they approx half-fill those huge boxes. And make them heavy.
You play as a unique character (each one has a distinct style and capabilities). 18 in each of GH and FH. My group has played between 25 and 30, but none of us has played all. I want to though - they're all different, and almost all I've played have been fun. I'll literally die of old age before I'm done with the characters we have
Each one has a mini, a small set of action cards, and a set of unique "buff" cards, so that takes space. But you only play with one (solo can play with more, but IMIO max practical would be three.
Something like 50 distinct monsters, including some bosses. Each has it's own action cards (a small amount of overlap, but not much.
We've played somewhere near 130 distinct scenarios IIRC. A lot anyway /lol. 2 campaigns done, doing the third (Frosthaven) now
Take a look on boardgamegeek and youtube to get an idea.
I'd guess everyone is playing Frosthaven now, so I think a "real gamer" like you should start there. A reminder though - it's a heavyweight, complex game. Lots of fun, but not something you should persuade non-gamer friend to "try out"
SO I suggest you check out Youtube. If it looks good, try it. The game is very well designed and implemented, so if you like that style of game play you'll this these games.
Ask me questions here of you like (you'll have plenty
BTW they're not cheap compared to smaller games, but they're actually good value for money. The way we see it we've paid something like USD 1 per hour of gameplay per person. And we've bought
everything, all the cards are sleeved, lots of convenience extras, etc, so we've spent enough for me to live on for a couple of months
BTW - you could probably find a group to play with if you like being social. I'm not very social (but get on ok with other people when I'm with them) ... and I got caught up in an extra FH group (once a week) by accident