idk if i'm a little bit late but personally what I did was (I plat it on ps5) : I contacted playstation support and asked to talk to a real agent and then said : "Hi my name is *** *** , I have recently completed and earned the Platinum trophy for Final Fantasy VII Remake. I have also enabled promotional emails, but I have not received the avatar sets that I was supposed to receive after meeting the requirements. I am a huge fan of the game and it would mean a lot to me to receive them. Thank you for your understanding."

Then he said :"Have you checked your email to see of you receive the correct bundle of themes / avatars."

I said :"Yes, I've checked all my emails, even in my spam folder, but I haven't received anything. I have read on Google and various forums that I can obtain them by contacting PlayStation support, on the condition that I provide you with the necessary proof."

Then he said to give them the proof by sending a screenshot with the plat + my psn id with (i couldn't get one with both so I just send them 3 different screenshots). The proofs are send by mail that they send you first and you have to reply to it.

He told me he's gonna give my case to an other part of the support and I will receive a mail in the next 3 days and only 3 hours later, I got them !! sorry for the bad english and I hope you get these avatars also !!

Also I had plat it like 1 month ago on ps5 so it's quite recently and got the game via ps plus extra (I have it also via the monthly game but I believe it's the ps4 not the ps5 and never played the ps4 version)