hello - that has to be super frustrating - hang in there!!
Suspecting your bryopsis is (getting) resistant. Not on the label but found somewhere online where you can dose tank at 2x rate... and that is what I did. My yellow tang did not do well (was near death a few hours after treatment start) so it 'vacationed' in QT hastily setup and then I had to reacclimate yellow tang weeks later back into main display tank (home). I also have an 180g so that meant 4 bottles since just 10 capsules in each of the bottles of Reef Flux I used - 2 bottles would be normal treatment for a 180g with ~20g sump. Corals, inverts, and all other fish did fine with Reef Flux at 2x dose, but recommend keeping an eye on everything/everyone in case you have different reaction. Yellow tangs do have reputation of being 'coal mine canaries' of reef tanks...
Since I was also doing Vibrant at same time for other nuisance algae it was so hard not to do water changes during Reef Flux treatment for our bryopsis.
My bryosis never came back, but lately I'm dealing with hair algae so bad I've finally broken down and ordered that BRS 4 FOOT UV light... it arrives today and we'll plumb it into one of my two sump return lines.