How to get rid of "System Data" on my iPhone SE?

Well, this is unfortunate. I did all the steps to remove the system data. Back up, did it. Did no impact. Restart, did it went down to 22gb then went to 39 gb. I have only one app. It is WuWa 10gb. Rest are at the mb. This is simply so frustrating. Even erase & all content. Remove it, NOW waited 5 days to recover. Now am at 39 gb. I have an iPhone 8, which is pretty old. Hopefully I can get a device that’s much better than the 64gb. Am struggling and don’t know any option to clear it which sucks. I even offload. Only remove NOTHING, barely anything. If I remove WuWa then it’ll be at 53 gb which is still high. That’s the only game I play which am so disappointed (and Roblox). So only 2 apps and 39 **** gb? How much does the storage hate me. I’ll eat the phone by deep frying it, IF it doesn’t fix.

[Re-Titled by Moderator]