Wow,you and the others took a really deep dive into it. My thought of it was more simpler on the conceptual level:
My suggestion was to narrow down the confrences into a single league table of today's method i.e 16 teams at each time(proper elimination of the bots syndrome+relevancy into any tier) which 8 teams would go into a 2 legged playoff against each other up until the finals which extended into the best of five(4 matches+a tie breaker of fifh match if neccesery). While only four teams would go for best of 3(3 matches+tie breaker if needed) at each phase(Relegation Semi's and Relegation final) and canceling of direct relegation.
Draft would stay as current system.
In addition,i do think that there is a place to TV prize money increase while intrdoucing a solidarity payments of 10% spreaded across tier two-four out of the highest tier TV deal pot(adjust the ratios per nation size and amount of active leagues) to allow both trainees and competitive teams exist mutually.
Also the OE Taxed amount of over spending should spread evenly accros that tier teams which comply into the BB rules.
Again,it is a lot WIP but these thoughts are relatively organaized.