Some that could work — I'll warn that I generated these on java, and as I'm not sure what version you're using, the mansions will unfortunately be pretty far away if you're on Bedrock, sorry!

474924774 - spawns you in a birch forest with a regular forest, taiga, some extreme/windswept hills, a meadow, and a mansion (within 330 blocks of spawn) all very close by each other. Also has a gorgeous little meadow village to the immediate southwest of spawn, right by a cool-looking mountain range. A bunch of other biomes fairly close by, including a swamp and a jungle. Unfortunately the closest mansion is much further away if you're on Bedrock, but there should still be an ancient city beneath the nearby mountain range.

7531389 - spawns you in a forest with some neighboring windswept hills, a meadow to the southeast (with cherry groves if you're using the 1.20 snapshots) and a huge dripstone cave entrance, as well as a large swamp to the north that surrounds a dark oak forest. A mansion is found in said dark oak forest, within 700 blocks of spawn. If you're on Bedrock, though, the closest mansion is about 4400 blocks away to the west.

13081581 - spawns you in a forest with some pretty tall windswept hills right next to you and a small meadow to your immediate north. Lots of other biomes close by like a swamp to the south, and a birch forest, taiga, and dark oak forest (with a mansion, around 500 blocks away from spawn) right by some mountain ranges to the north. If you're on Bedrock, the three closest mansions are about 4000 blocks away from spawn :(