How can I recover photos I accidentally deleted (iPhone)?

If you go to the Photos app, Utilities section, and select "Recently Deleted" you may be able to get them back. Good luck to you.

I tried that but couldn't recover all of them, is there any other way? I really don't want to lose these photos!

Yeah, past the 30 day mark they are probably permanently gone. If you've backed up your files you can retrieve them from there too.

Check your archive and trash folders. They might be in there!

There are third-party websites that claim to be able to help restore deleted photos, you could try one of those? But I'd be cautious, most of them seem scammy. This might just be a learning experience.

if you back up your phone, then you can restore your device from a recent backup and you should get your pix back. but save any new photos or files or anything you need somewhere else before restoring or you'll lose those as well

If you want to delete a pic from google photos but not from your phone, turn off google photos backup in your app settings. Then, delete the pic from google photos and it will stay on your phone.