I felt the same way for a period. Like other than practice, practice, practice (JobTestPrep has a lot of practice WGs), there isn’t a lot more you can do.
I think they’re a test where unless you’re naturally inclined to them, you struggle regardless of the amount of practice you put in. Honestly, if you feel they continually let you down in applications, I would just focus on firms that don’t use the WG as part of their recruitment process (and that’s the majority).
If you focus on firms that use SJTs or no tests at all, it may put you in a better position as there’s nothing worse than spending hours on an application only to not even have it reviewed due to a weak WG. Best of luck!