Maybe look into PipeWire, Reaper in jack mode works fine connected to PipeWire for me, without any of the problems you mentioned.
It is quite possible that your desktop audio already uses PipeWire depending on your distribution, you would need to look at latency settings if you want live playback.
At some point, uppercase letters were written without accent in French. I’m unsure where this comes from, but I heard this was due to the limitations of printing presses, and then typewriters kept the convention.
In any case, the style is quite out of fashion today, but I know people who still write (handwriting and typing) without using accented uppercase letters.