Remove speed UHC and replace it with "mini UHC" where its like 8 players per game, because its impossible to reach the 24/36 player capacity so UHC players can't even get into games anymore.
This would require the map to be smaller since there's less players, simple fix = make starting world border size smaller.
This shouldn't take too long to make + I'm pretty sure none of the UHC players want "custom world events" or "custom mobs", "custom terrain" etc, I'm fairly certain they just want a vanilla world UHC with no customisations barring no ocean/deep ocean biomes and a possible deathmatch arena at the end.
This would require the map to be smaller since there's less players, simple fix = make starting world border size smaller.
This shouldn't take too long to make + I'm pretty sure none of the UHC players want "custom world events" or "custom mobs", "custom terrain" etc, I'm fairly certain they just want a vanilla world UHC with no customisations barring no ocean/deep ocean biomes and a possible deathmatch arena at the end.