You've already listed the major drawbacks of each. I've owned both and I don't think that the V8 in the GX is all that much better than the 4Runner. The extra gear in the transmission is nice. The back door sucks, the interior is more dated than the already dated 4Runner. There's no denying that it has more luxury and slightly more comfort but we aren't comparing the luxury delta between a 4Runner and a LX570, the GX is just slightly better.

I wouldn't fault you for choosing the GX if the nicer appointments and ride are important to you and I feel that the 2020 TRD Pro is grossly over priced so there's that. Best of luck with your decision, both have their merits.