The Seed for a Mushroom Island near spawn with alot of cool features is 31622694 for 1.18.0 . You spawn at the edge of a Desert with a Desert Village, a Jungle, and a Shattered Savannah Plateau all nearby! Only going down 200 Blocks from spawn on the X Axis in the Warm Ocean reveals the Mushroom Island. While there are no Ocean Monuments in this Ocean, you're getting a Village, a Jungle, and a Mushroom Island all right at spawn!

Here are all the wonderful features of what you can find near spawn:

Ruined Portal: 321, 61, 354
Desert Village: 197, 72, 259
Azalea Tree: 118, 61, 2
Lush Cave (Small) 118, -12, 2
Completely Enclosed Amethyst Geode: 118, 32, 2
Mushroom Island: -259, 63, 193
Zombie Dungeon: 131, -11, -3
Spider Dungeon: 133, -6, 16
Azalea Tree: 542, 63, -44
Lush Cave (Massive): 542, -14, -44
Abandoned Mineshaft: 581, -40, 90
Abandoned Mineshaft: 579, -35, -139

So near spawn ontop of what I mentioned above on the surface, you can gain easy access to an enclosed Amethyst Geode, a Zombie Dungeon, a Spider Dungeon, a Ruined Portal, and two Lush Caves, one of which is massive! Note that in future hotfixes, generated structures can change position or not generate at all, so get this seed now if you want to generate it.