S24 taking ages to upload Google Photos pictures

I've used different phones and uploading pictures to Google Photos was pressing a button and waiting for it to finish upload, in reasonable time.

I've recently got an S24 and not only it takes ages to upload, but anything else you're doing with the phone, and it stops uploading. If you shut off the screen, it stops uploading. If you're not constantly fiddling with the Google Photos app, it also stops uploading

I did press "Recent Apps" and selected "Keep open", and it's still not working. It's there some aggressive battery optimization setting I'm not aware of?