Since 1.9, minecraft added a Health Limit to mobs. This limits the Health to 1024. The Mod Abyssalcraft removes the limit but the max version for it is 1.12.2. As most of the bosses (and a few mobs) have over 2000 health and there are no 1.14.4 mods that fix the issue. My idea is for a box that you can check that allows the health limit to be removed if the mod is running. This is possible as the mod Abyssalcraft has done it. The workspace would take a bit longer to setup but it would be worth it. You could also enable it or disable it anytime while working on the mod. This would make the mods more fun to play and would help a lot. (Fun Spoiler for my mod, there is a boss that will have 2600 HP called penumbra. This boss does high melee damage and spawns in explosive bombs!)
Issue comments
to use it in MCreator's environment you would need this deobf version though:
https://www.curseforge.com/minecraft/mc-mods/attributefix/files/2922861
assuming you are on 1.15
then you would want this file instead: https://www.curseforge.com/minecraft/mc-mods/attributefix/files/2827771
https://www.curseforge.com/minecraft/mc-mods/attributefix/files/3232228
the attributefix deobf version of 1.16.5
If you want more than 1024 use external apis and code.