There is no need to uninstall it…
just switch the driver to the interface you are using.
I use a fireface UFX and use the MR816 only for additional inputs and monitoring the amp sounds. I have the extension installed all the time.
By the way the RME has at 256 samples LESS roundtrip latency than the Steinberg at 128 samples. And with Rme I can go down to 64 samples on a busy project, when the Steinberg begins to crackle at 256 samples already. SB needs to do something with their drivers…