Hey, FMPerception is great, but it is indeed un-opinionated. It won't really tell you why a part of your solution is slow.
acording to an RCC training video, unnecessary relationships strain FileMaker, presumably affecting performance.
Don't take this at face value. While eliminating unnecessary schema is good, I'll venture that extra TOs/relationships are unlikely to be the performance culprit. They do affect startup speed, but not really general usage (with some exceptions). See this discussion:
My advice for performance tuning your solution is very unglamorous. Identify something about your solution that is slow, and dig into that issue specifically.
Maybe a list view scrolls slowly. Is it the unstored calculation that is showing on the line, maybe a slow conditional formatting. Maybe you're showing related data. Try removing objects until it's fast and zero in on the slow bits and try to fix those.
Or if you have a slow script... benchmark each section. Maybe it's the loop in the middle that's slow, or an ExecuteSQL call.
Does your solution open slowly, try disabling your startup script. If it's still slow THEN it might be the relationship graph that is slowing it down. But I wouldn't make any changes until you've tested a few hypotheses.
Best,J