Messages and Photos are not being Offloaded to iCloud

This is extremely frustrating. I’ve had photos and messages synced to iCloud for a while, and instead of offloading to iCloud which is what my phone is supposed to do (I’ve checked and unchecked and checked again the option to optimize phone storage), it still chooses instead to store all my messages and photos on my phone, despite me still having to click on thumbnails to download my photos from iCloud anytime I want to look at them or send them. I did an entire factory reset and things seemed to be working for a couple days, and then bam, I’m back to a full phone again because nothing will offload. I have plenty of space on iCloud too so that’s not the issue either. I’ve done the suggested “turn off icloud sync and back on again” but it does absolutely nothing. I’m at my wit’s end with this.