How can I recover photos that I backup on iCloud if I deleted them on iPhone?

i have started using the i cloud memory backup for photos especially, and since i didnt want some stuff to take up space on my phone i think i might have deleted them from my phone because i thought they would stay on the cloud, and it was a longer time ago, i cant recover them myself form the trash can, and ive checked my i cloud as well they are not there, is there a way you can recover them for me because there were so many important memories that got lost just because i didnt know that once you delete photos from your phone they get deleted on the i cloud as well

[Re-Titled by Moderator]