As GC's main purpose is to give opportunities to marginalized groups, making it a "special division", What if we prohibit GCC winners from competing in the GC bubble in the future and instead make them compete in T2/Challengers? I think they've been given enough opportunity to show their worth (so the argument "lack of opportunity" won't be relevant anymore), and with the championship in hand they sure are the best GC can offer. Also, this can help the GC scene be more balanced and allow future talents to rise to the ranks.
I got this inspiration from the Formula 2 Championships, where the champions are not allowed to compete at the same level anymore, Allowing the best drivers from the F3 to compete.