I think you will be fine with the 3.73 and 20" wheels. Just buy a tire with a slightly lower profile, to match the overall tire diameter/circumference.

P245/45R20 = 245/25.4x.45x2= 8.68+20=28.68”
P235/55R18 = 235/25.4x.55x2= 10.18+18=28.18”

See if there is a
P255/35R20? 27.03"
P255/40R20? 28.03"

I have seen Nitto 555 Extreme P265/ZR50/18, (265/25.4x.50x2= 10.43 +18= 28.43")