Flat worlds With Many Add-ons Infinite Loads

When loading my flat world with the same add-ons as a regular world, it gets stuck in the middle of the loading screen and never finishes loading. However, regular worlds load successfully with the same add-ons.I’ve let it run for up to an hour with no changes. Also the world seems to not like too many blocks added to the game. Add-ons that don’t add blocks work still, while furniture related add-ons do not. Or just add-ons that add a lot of items.

You can reproduce this by creating a flat world on realms,I added 6 add-ons relating to furniture. Other types of add-ons do not cause this issue.(probably of small enough and adds little to no blocks.)Then try to load the realm it will get stuck loading halfway, then take one add-on off. The world will then load. Pictures below of infinite load.