80%-100% Possible, yay or nay?

I am incredibly blessed and happy I’ve got what I’ve got; I had a really good C&P doc and —still in disbelief as I know folks in here have sacrificed more than I have. I appreciate your patience in this question:

I recently had a consultation with one of those VA increase type outfits. With what I’m currently rated for, it’s possible to increase to 90% —I don’t think that’s worth poking the bear for.

A few items I was denied for were due to lack of medical evidence. I never went to base doc for them but are definitely because of my other service-connect conditions (and are worsening, especially as I get older and fatter…)

Going to route of filing a supplemental for secondaries (after getting a diagnosis) Is this even possible for me and how long would that process take?

Thanks guys I appreciate all the insights