Hey @caddyblueyellow, I’m terribly sorry to do this - it’s something I pretty much never do - but I’m straight up going to have to tap out of this one at this point.
While I wish you all the luck in getting it working - and I know it can, I’ve spent the hours of effort fiddling about learning how to do it for one of my apps I just really wanted to work in a subfolder before and had success.
But I don’t know your upstream apps, I can’t see the exact data coming and going or how it needs to be manipulated. And even if I was there in person with hands on the data, last time I did it it took me literal hours to get a working end result. It was messy and complicated but it functioned… Until the app eventually changed the way it issued links in one update. I did explicitly say in the thread I linked earlier:
So again I’m sorry to just straight up tap out, but rather than spend probably days going back and forth and trying to pick it apart through the lens of your forum posts, I’m going to simply say that my strong recommendation is to give it a subdomain and be done with it.