Hard to tell from the photos, but are you trying to use a post-mount caliper on a flat mount frame with an adaptor, thus would solve all problems buy purchasing a new caliper...?
Er yes- that’s basically it.
The main reason for my stubbornness is that I got a good deal on the Hy/Rd brakes and had the 160mm post mount adaptors in my parts bin
I went for flat mount on the frame/forks for futureproofing …
Future proof but not present proof... Looking great though, I wasn't sure about the colour initially but it looks loads better built up for some reason.
Hard to tell from the photos, but are you trying to use a post-mount caliper on a flat mount frame with an adaptor, thus would solve all problems buy purchasing a new caliper...?