anonprivacypro Personally, if I were in your situation, I'd figure out how to group profiles better to suit my needs, back up data, then factory reset and start fresh.
There could be different reasons for the phone running slowly. It could be apps running in the background, maybe one or more are using more resources than necessary. Another possibility is developer options is enabled and some setting has been modified causing the phone to act differently.
Also, you're saying that the issue isn't that other user profiles aren't running in the background. How do you know that? Is it still sluggish after a restart?