I shared the same frustration, but I finally gave up, and guess what, I was able to fulfill my projects and have a good insight about what my layout will be even with ~5cm difference. I learned to relax about absolute measures and think more about feeling and subjective dimensions.
Described in programming terms: You try to type the weird dynamic object you have to deal with in Typescript but after spending too much time, you learn to relax about types and just write it in JS and it feels like it's working most of the time.
Don't forget the power of `as const` and type guards for tricky dynamic types! Especially for function params that accept multiple complex object types.
