Photos app stopped working, worse after I updated to High Sierra 10.13.6

High Sierra is a very old system version. If you are now running macOS 10.13.6, High Sierra, you are using a system version from 2018. You cannot open any Photos Library on High Sierra, that has been modified by Photos 8 on macOS 12 Monterey. Did you really downgrade to High Sierra or rather upgrade from macOS 12 Monterey to macOS 13 Ventura?

If you have upgraded to Photos 8 on macOS 13 Ventura, the location of your Photos Libraries matters a lot more than previously. The older system versions let you use libraries on external volumes, where the library could get damaged. Ventura is more restrictive. If your Photos Libraries are not stored in your Pictures folder on your internal drive or on an external volume prepared as described here: Move your Photos library to save space on your Mac - Apple Support. move a library to your Pictures folder and try to open it there. The Photos Libraries need to be on a volume formatted macOS Extended (Journaled) or APFS, not on a volume used by Time Machine, and on no account on a network share. Use only external volumes with a wired connection, not a NAS.

Ventura is very different from your current system version - any system later than macOS 10.15 Catalina is, because the older apps and system frameworks needing 32-bit code will no longer be supported. You might try to upgrade in smaller steps, first to macOS 10.14 Mojave, the last system version supporting iPhoto, Aperture, QuickTime Player 7, and other 32-bit applications. Then try to find out, which other apps you need will no longer work on a newer system version. in particular, check your videos and your image files and when in doubt, convert them to a format, that will be supported on the system you want to upgrade to. I converted all videos to the codecs H.264 or HEVC, and all image files to HEIC, JPEG; PNG or TIFF, and kept the RAW files RAW, before I upgraded from Mojave to a 64-bit system version. This took care of the media files in my Photos Libraries, but not of the videos and photos embedded in presentations, like lecture note. I am still coming occasionally across media files that can no longer be opened on Ventura, but I kept two older macs on Mojave for such emergencies. To check for compatibility with newer system versions try App Compatibility Table - RoaringApps - App compatibility and feature support for OS X & iOS

or go64. Or look at the system profiler >About this Mac > More details.

For media files also: About legacy media in iMovie for macOS - Apple Support