I suppose the question is whether the pocket floor and pocket heel were both flat, so you got maximum contact between the two. Sometimes, the tenon extension can curve upwards, giving a gap somewhere on the join that gives a weak glue area.

And I can see in the pictures that you left the finish off the neck pocket on the body, but I don’t know where you stopped with the finish on the neck itself. The further into the pocket area the finish goes, the weaker the joint will be (one reason why I prefer to glue my necks on before adding any finish, so I get the maximum glue area - important on a guitar like an SG with a small contact area). Wood glue sticks to the cellulose in the wood, so you need bare wood to bare wood. Glue on the finish is very weak.

I would certainly have a go at resetting the neck. You might see some cracks opening up already when you pull the neck. You could try steaming it over a pan of boiling water (it’s mainly the heat that weakens the glue, but the steam helps to carry that into cracks).

Then check for both mating surfaces being flat and being clear of finish. If you need to level a surface, then double check the neck angle afterwards.

I’ve always assumed that the glue Pit Bull supply is original Titebond (the red label one), but I’m now not 100% sure. So I would go and get some of that.

If you are really happy with the neck angle, you could use epoxy instead, as that will bridge small gaps with a strong bond that Titebond won’t. But you won’t be able to get the neck off again.

The problem with standard Fender-sized neck plates is that the hole spacing is too big (I think) to get all 4 screws into the thick part of the neck, so you’d need much shorter screws at the back, and probably shorter than normal screws at the front as the overall body+neck depth is less on an SG than say on a Strat.