attachments on messages not downloading

So a couple months ago i accidentally deleted a text message conversation of 5 years, so i reset my phone and got all my data back from my last backup so i ended up not losing anything. but when i did that i noticed all my picture attachments didn’t show up in messages. i knew they were still there because they’re saved on my icloud and i could scroll up and find them in my messages, but i couldn’t access them by clicking “i “ and looking at all of them. it’s annoying because all my conversations are 5+ years old, so i can’t just scroll up to find a picture. just the other day i saw on my messages that all my pictures attachments could be downloaded from icloud but when i went to click it it just went away and then it wasn’t showing up anymore. i don’t know how to get them downloaded onto my phone again? i’m scared to keep trying to click download because then the option keeps disappearing and i really want them back on my phone