I'd say white vinegar will help loosen the white "wormy" things...& a no soap fine-ish "scrubby" pad too. Repeat as needed, it may take a few tries.
Your Rena (2?) filter looks to need new coarse & medium sponges, some bio bits...maybe a filter pad, it's kind of optional. I don't think I'd bother with the carbon pouch, it's likely shot (carbon is very optional). Don't forget to clean the impellor, gently! Crud has likely dried on it, again white vinegar & be gentle...ish.
You can carefully razor blade the tank after a vinegar soak. Do not blade into the silicone!! There might be some etching of the glass from mineral deposits. Don't panic, fill it with water & see if they're noticeible. If 1 side looks better let that be your tank front.
I don't know what the red round thing is...