Originally posted by _I_:

map seed = Guest
https://valheim-map.world/?seed=Guest&offset=-883%2C274&zoom=0.600&view=0&ver=0.212.7
start island has almost no swamp and no swamp crypts
moder is surrounded by plains or mistlands

post yours

That doesn't look like a bad seed to me. There's a Bonemass right next to spawn with meadows and black forest.

Having Moder surrounded by plains is fairly normal, and shouldn't be a problem. If you're ready to take on Moder, you should be ready for the plains. The Moder out in mistlands would be tough, but the rest of them all have black forest to land on, and then it's just a short hop across plains to the mountain.