I never used anything called "feelz op", those are you words. I'd submit if you can show me in the rules where it says you can use Total Character Levels to gain Epic Boons, but you can't because no such thing exists in that section. The MC section specifically states where TCL's apply, and Boons aren't listed.
'Level' is defined in the character advancement table. Any time the game refers to level rather than <class> level, it means total character level.
Just because you state something doesn't make it true. You have not articulated a reason for your statement outside of the equivalent of "feelz op". The text of the ability score improvement feature says "You gain the Ability Score Improvement feat or another feat of your choice for which you qualify." Epic boon feats are feats. They do not require having the epic boon feature nor do they require you be class level 19. Therefore you are eligible if you multiclass and plan it in such a way to get an ability score improvement feature at character level 19 and character level 20.
I never used anything called "feelz op", those are you words. I'd submit if you can show me in the rules where it says you can use Total Character Levels to gain Epic Boons, but you can't because no such thing exists in that section. The MC section specifically states where TCL's apply, and Boons aren't listed. Neither are Feats for that matter. If it's not a rule, it doesn't exists and it's just Table Settings/Homebrew.
You literally just made the argument against your position. No where does it say class level. When features mean class level they say class level. Invocations specify class level, magic item plans specify class level, epic boons do not. By your own logic your position is homebrew because you are adding to what is written in the rules to get a class level interpretation. Furthermore level is defined in the creating a character chapter, level advancement section and part of gaining a level is to choose a class. That section shows that level is distinct from class level. When features do not specify class level then they don't use class level. A perfect example of this is cantrips. By your ruling a thief rogue who took true strike through a 2 level wizard dip would never get the additional damage since it just says level, like epic boons.
'Level' is defined in the character advancement table. Any time the game refers to level rather than <class> level, it means total character level.
You literally just made the argument against your position. No where does it say class level. When features mean class level they say class level. Invocations specify class level, magic item plans specify class level, epic boons do not. By your own logic your position is homebrew because you are adding to what is written in the rules to get a class level interpretation. Furthermore level is defined in the creating a character chapter, level advancement section and part of gaining a level is to choose a class. That section shows that level is distinct from class level. When features do not specify class level then they don't use class level. A perfect example of this is cantrips. By your ruling a thief rogue who took true strike through a 2 level wizard dip would never get the additional damage since it just says level, like epic boons.