Is abiword foss?
It is the most reasonable of editors/wp I have found, LO gives me a headache looking at 1000 menus/items.
The gtk2 version is stable as a rock, despite of some bad wrap it got last few years.
Many people browse 4-5 pages a day, see a few emails, print a few pdfs, and a core2duo, or x4, for 40#/$/Eu a box run flawlessly with linux and xfce/lxde for example.
Even video-conferencing works fine.
2 Do you have libnvme and nvme-cli installed? If no, try them, if yes look up things on the manuals. It may be that your bootloader can't read/mount from the nvme
3 Ever since systemd-boot appeared things have been not working so well, now, have they?
On magnetic disk there is physical location for each bit of data written, for ssd it is all virtual space handled by internal software simulating a magnetic drive. The variation from disk to disk is much higher than the sensitivity of the fs.
You want accuracy and reliability of data storage, use HDD and Raid!
A file system and a raid setup all in one with facebook's code for de-/compression ... yet another piece of software that tries to do the work for several others.
ext4 will rarely have extreme loads unless all you do is backup and mirroring. For more accurate data read/write and better checks use xfs and external journaling. On M2 it is by far the fastest solution and far more secure than ext.