My reflex is to respond with: NextCloud...but as much as I'm a fan of nextcloud, i acknowledge that it either requires your time to manage a nextcloud server, or your money for you to pay a nextcloud host provider to do it for you. Which made me pause and step back and ask (rhetorically), what your requirements for an alternative might be. Having (rhetorically asked that), i'm going to just give you a list of links that provide suggestions for alternatives to goolg e services - presumably including alts to google photos. Here goes (in no particular order)...

https://www.privacytools.io/

https://degoogle.jmoore.dev/

https://goodreports.com/ (This one is actually relatively new)

https://ethical.net/resources/

https://switching.software/

And, then of course, a classic: https://prism-break.org/en/

Good luck to you!

Haven't tried myself, but a friend of mine was talking up Amazon's offering. Apparently one of the big benefits is that they store your photos 100% raw as you took them so no reduction in quality to save space. Apparently with your prime membership you get unlimited storage of full resolution included ie free. Guess Caveat for this option is having a prime membership with Amazon.

I'm working on a self-hosted one: https://photostructure.com/faq/why-photostructure/

You're welcome to try out the beta for free, in exchange for your feedback.

PhotoStructure is designed to be simple to install and run. Libraries are uniquely cross-platform, cross-computer, and tested to scale comfortably to 500k+ assets. You can run the windows desktop edition, put your library on an external drive, move the drive to your Mac, automatically import whatever's on that computer, and sweep all your photos (JPEG and RAW) and videos (with auto-transcoding) into one tidy, de-duplicated folder hierarchy.

The UI is web-based and mobile-friendly. The docker image runs happily on NASes and anywhere else docker runs.