It is possible to improve on 6hrs a week. Mileage is utterly irrelevant. A proper targetted training schedule with periodisation, taper and a realistic race schedule will achieve your goals.
I’m not dissimilar but I’ve spent on coaching and understanding training. Until you do this you are giving yourself a massive handicap. Your race schedule is symptomatic. If you truly give your all on Wednesday it’s unlikely you will be able to do a high quality session until Saturday. I doubt a club run is high quality in terms of time in zone.
You also have to decide if 24:12 or xco is your priority and train for one ignoring results in the other.
Doing the same thing time after time and expecting different results is the definition of stupidity. Your Anthem gummed up last year – why would it not this year in the same conditions?
As we had this exact same discussion approx 12 months ago you really should break this cycle.