If you feel the system is too far gone and you have spare SSD, then a fresh install would be your best bet.
In the live environment (Solus on USB stick), you can copy any file to the spare SSD.
- Attach spare SSD to your computer
- Boot into the live environment
- Copy your file via terminal of file manager to the spare SSD.
After all the file you deemed worth saving is already copied over to the spare SSD, you can do fresh install overwriting the old install. Make sure to use "Delete Disk" option in the installer, so no broken leftover file from the old install remain.
TO BE PERFECTLY SAFE detach the spare SSD first before doing the fresh install, so you do not accidentally overwriting the spare SSD with your backup data there. After the install is success, you can reattach it and copy back the files to the fresh new install.