They could increase A LOT players agency/creativity if custom mechanics weren't so overpowered.
If D&D is about player's agency and creativity, let us also only play with D&D rules and spells and class abilities rather than impose us a good way of playing.
I'm 100% fine with their will to add more things and even silly things I won't use (like throwing boots or ennemies)... But please let me play this incredible game how I want to play it...
A better balance between custom rules and RAW mechanics is the only solution so players can CHOOSE and use THEIR creativity rather than yours.