Facebook messenger not syncing on my new phone or computer from my old iPhone, only showing messages up to March 24

I transferred everything to my new iPhone. When I go on fb messenger, it’s only showing me messages from March 24. The order of the messages and the date I last spoke to people is correct but when I go on individual chats they’re old messages. I have deleted and reinstalled so many times, updated the phone, all the sync options and back up are turned on. Even when I log in on a laptop or computer it’s still not showing my latest messages, yet if I log into my partners facebook on the new phone it has all of his latest messages so it seems to be an issue with just my Facebook. Any ideas please, thanks