In reply to JonC:
There's one line in your well-written (and, in my experience, extremely common) plea which stuck out for me:
> I'm not really into bouldering or redpointing, which I know isn't very helpful in terms of strength gains
This suggests that, despite writing 5ish paragraphs of text asking for help, deep down you know exactly what you could be doing to improve your grade. But if you don't enjoy sport climbing and bouldering,
there's no sense in forcing yourself to try.
The problem with E2 classics such as Vector and Left Wall is that if onsight 6a+/6b "on a good day" then you're very likely to fail on either of these.
My suggestion would be to target E1 and tick as many as you can. My first port of call would be Pembrokeshire where you are practically tripping over 3* soft-touch E1 straight from the carpark in St.Govans.
However from the routes you mentioned in your post you seem to know North Wales, so my season ticklist would start off something like:
Bow-Shaped/Great Slab combo (HVS at Cloggy, good intro)
Brant Direct (technical HVS in the pass)
Cemetary Gates (soft E1)
Superdirect (best E1 EVA!!!!111)
Cenotaph Corner (hard E1)
The Plum (take a big cam)
and lots of soft touches on Slate such as Looning the Tube, Seams the Same
...and then move on to more committing routes such as White Slab, Gogarth etc. Then you start looking at E2.
Good luck, I was once where you were, and the following years were undoubtedly the best ones of my climbing-life (so far)!