@Tench745 Hey mate. there are things you can do to make it fly better then it does. Tuning methods have been refined more and is pretty easy to walk someone thru it. There are things you can do like soft mount the flight controller to isolate the vibrations from such an old set up.
Pretty much that is all you can do without spending money.
The hard thing is the FC is so far out of date now its no longer supported so you have to work with what it is flashed on. That means no filtering just pids and know how. The nice thing is a simple change in the rates will do you the most good to get started on fpv with. You can cut them back enough to make it fly like a tiny whoop.
Basically what we fly today is like win 7 and what you are flying is win 95 at best in comparison.
The best way to start is to down scale the rates a lot. Fly line of sight to train up on that muscle memory. THEN go for fpv again without any auto leveling at all.
I dont have a car nor a licence to drive anymore after getting hurt other wise I could easily come meet you as you are only about an hour n a half away from me and help you get it all going better. Maybe pass on some old parts to upgrade it a bit with after sorting out what matches what and making sure what all in my pile o parts actually works hehe.