My comment only concerns Windows:
I did some comparative tests in several situations using:
- the same programs and plugins in Windows 11
- with either an RME interface or a cheap Steinberg UR22
- on a recent 2022 PC i7 12700H 32GB RAM
- on an old 2012 PC i5 3320M 8GB RAM
In all same cases, RME has slightly less latency than Steinberg.
In one specific case, the old PC with the Steinberg + Windows fully optimised for audio has less latency than the recent PC with RME + non-optimised Windows PC.
This is due to the fact that, with non-optimised Windows, the impressive number of unnecessary interruptions from sub-programmes, background tasks, system routines, etc, will lead to excessive consumption of processor cycles, resulting in audio crackles that need to be compensated for by increasing the buffer size.
The result is higher latency.