The vast majority of your character data (characters, levels, equipment, items, and progress of various types) is stored on SE's servers and not on your PS4. So reinstalling won't even touch any of that. There is some configuration data (including your hotbars, gear sets, macros, and HUD layout) that's stored locally on your PS4, but even that's separate from the main game data.

The PS4 stores game data separately from save files, and SE uses save files to store local configuration settings. (There's one save file for global settings, and then one save file per character for character-specific settings.) When you uninstall a PS4 game, it removes the game data but leaves save files alone. While it's generally a good idea to back up save files just in case, they should be safe through deleting and reinstalling the game.



Wish you the best of luck getting your problem fixed. Afraid I can't offer much help, though. The only time I've had a similar issue it was because of a faulty router. Rebooting the router fixed it long enough to get me in. (And then replacing it with a new router was the more lasting fix.)