I Mashed a bit Too High on High Grav Beer

I pitched yeast on a Dark Belgian Strong Ale back on September 19th. Here is the recipe:

Belgian Pilsner 7 lbs, 0 oz
Belgian Pale Ale 7 lbs, 0 oz
Caramel Pils 1 lbs, 0 oz
D-180 Dark Candi Syrup 1 lbs, 0 oz
D-45 Amber Candi Syrup 1 lbs, 0 oz
D-90 Dark Candi Syrup 1 lbs, 0 oz
Northern Brewer Pellets 1 oz @ 60 mins
Styrian Golding Pellets 1 oz @ 25 mins
Hersbrucker, German Pellets 1 oz @ 20 mins
White Labs Abbey Ale

My OG was 1.096 and after 4 weeks it had dropped to 1.034. The expected FG was supposed to be 1.023 however after leaving it an additional week, the gravity had only dropped 2 more points.

The recipe called for a 148˚F mash which I missed. It mashed closer to 154˚F due to a few distractions. The temp has been held at 64˚F except for about 3 days that I let it rise to about 74˚F after the first few days of fermentation.

It this as low as it will likely go due to the higher mash temp? Should I try to raise the temp a bit? I'm not sure how high I can raise it at this point as my basement is cooling off. It tastes really good now but I was hoping for a bit drier beer. Thoughts?

Try a fast ferment test. Anything else will just be guessing.