Recovering Photos from iPhone Backup Without Restoring iPhone

Hello, for some reason, I have photos missing from my iPhone from roughly 2018-2020. I know I backed up my IPhone, including photos, to an external disk during that time, but I can't access them from my Mac, and I can't restore my iPhone to that backup without losing all my photos since then (as I understand it from this answer).

1. Is there any way for me to access those photos WITHOUT restoring my iPhone from that old backup?

If not, will the following procedure work?

1. Get access to another iPhone (I have my wife's old one, wiped)
2. Sign into my iCloud on this iphone
3. Move the old iPhone backup from me external disk to my Mac
4. Use iTunes (or Device Manager) to restore the iPhone from this old backup
5. Then, back up these photos to iCloud
6. Wipe the phone
7. The old photos will now display in my photo stream

Please let me know if this would work or (much preferably) if there is an easier way!