Correction: I started to get INFO messages (and not errors). Still, they are clutter.
Now I appended Environment=MONERO_RANDOMX_UMASK=1 to the [Service] section, and these INFO messages with exceptions and stacktraces seem to be gone for now. Not sure whether this is a permanent fix or whether they will reappear and more has to be done. From a programming point of view on the original setup, a constantly thrown exception is wasteful; detecting the file system and adapting to its capabilities properly right from the startup of monerod would be a better way.
