UPDATE - I was able to get a good solution to this for the 18,19, and 2020 Sequoia.
1. Using a flat metal bracket (approx 2"x6'"), I bent one end at 90 degrees and in the shape of the top dash above where the chrome trim (directly above the hazard button). When bending the 90 degrees, angle slightly off center in your vice to match the shape of the dash allows for this to be more vertical.
2. Depending on your phone mount, you may need to trim off about an inch of the non-bent end of your metal bracket.
3. Cover the bent part with painters tape since this will be wedged in between the dash trim and top dash. Cover the rest in black flex-seal.
4. Attach your phone mount and file the screw points down flat as you can so as to not scratch your dash.
5. Use 3M two sided tape where the metal meets the dash.
The 3M and wedge-in-dash make for a very strong and stable mount.
Didn't want to drill holes for the wire so affixed them to the dash and ran behind the lower cowl to a power source.
Can get to the hazard button, there's plenty of clearance to work the wiper wand, and nothing in the way of the right air register.
Hope this helps.