iPhone photos cannot be deleted & the more photos I delete the less storage space I have?

Hello… my phone (iPhone 11) has been acting up for a few years now. I never have any storage space even though I no longer have any apps, photos, etc. because I've already deleted everything (it's all in the cloud, and the cloud still has storage space). The more I delete, the less storage space I have. Sometimes I can't even delete photos in the album because as soon as I press delete, the pictures jump back into the album. I can't use WhatsApp, I can't open my emails anymore because I keep getting the message that there's not enough storage space. On top of that , my phone crashes a lot. I'm using it normally, but suddenly it goes black and the loading circle appears (like when you turn it back on). As soon as it boots up again (I don't have to enter a PIN), some of my apps are gone; the name is still there, but I don't see an icon (I can also press "into the void" and the app opens normally). But if I completely turn off my phone, for example, so that I have to enter the PIN when I boot it up, it sometimes works again. I can use everything and have more storage space (even though I didn't delete anything, I just turned it back on). Is this a virus ?

Thank you in advance!!!