My Huawei P Smart Gallery Pictures Have Disappeared

Ever since I got my hands on the Huawei 2021 P Smart phone, I've been dealing with this annoying issue where pictures in my gallery mysteriously vanish. Images that are downloaded from WhatsApp or Instagram tend to disappear after a few weeks, without being stored in the trash bin. I previously filed a complaint about this matter, but unfortunately, I did not receive any response. I'm really disappointed with this phone because I lost all of my pictures. Can you give me some advice on what to do? We really need to address this problem right away.