I'm not sure you'll have a lot of company with those complaints. That being said, I made sure to stay away from the 2020 when I was ready to buy my Explorer (grabbed a low mileage very clean 2017 Sport).
I was really excited about this next generation Explorer built around a "rear-drive" platform, but was struck by how bad the launch was due to excessive production quality issues. Yes, all new gen vehicles have some teething issues, but the 2020 Explorer was horrendous. Ford ended up having to setup a facility to do nothing but fix these things post production, which was well after the initial wave was in market.
I will agree with you about the transmission concern - from my perspective it's the only real engineering issue on your list - and actually ended up being my number one concern why to not consider the 2020 Explorer and potentially 2021 and beyond.
Ford / GM did a joint venture on a new transmission, with the Ford being a longitudinal 10-speed (10R80 and 10R140), starting for select 2017 production year vehicles. It's in the 2017-2020 F150 and It's a piece of junk. I ended up getting 2020 F150 loaner from my local dealer earlier this year - had less than 500 miles on it - and the transmission was horrible. It sometimes would jumped gears, got stuck in 3rd gear on two occasions, and routinely hard-shifted for no apparent reason. There's numerous TSBs and some class action lawsuits.
My understanding is the 2020 Explorer 10-speed (10R60) is basically the same 'hard-parts' but is running different components in the guts of the thing. While maybe the 10R60 doesn't have the same issues as the 10R80, to me it's not worth the +$50K to experiment on especially when it comes to an automatic transmission.
My 2017 Explorer Sport seems to be rock solid all around. I'm pushing 60K miles and drive the hell out of the thing, which includes a cold air intake and some additional performance upgrades from Livernois (3-bar map sensor, high flow thermostat, etc. and their performance tunes).
Cheers