Saw some Qs, so I thought I'd answer as I am currently the proud owner of a 2020 XLT FX4 Expy with HD tow package and working on making it more off-road worthy. As a side note, the Expy's room, power, towing, and economy lead the class (maybe the '21 Tahoes can match/exceed some?). This thing is FAST, even on 87 octane (faster with 91+, confirmed by car mags).
This is THE Expy off-road combo as it comes with skid plates, 2-HI, AWD, 4-HI (center diff-lock), proper 4-LOW, 3.73s, and push button on/off rear E-locker (which you can run in 2wd). Also has a true "neutral" for dolly towing. The Fx4 comes with different terrain control/sport modes, hill descent, and the HD adds more cooling for the transmission (and 9100lbs of towing) with HD tow (both options net the 3.73s). The FX4 comes with Michelin Primacy 275/65-18s (32.1 inch) highway tires, but will take moderately wider 33s w/o rubbing, but a 1.5 inch Bilstein 5100 shock lift helps here. The wells are pretty tight...
TTBOMK, this Expy is the lightest weight off-road/heavy tow combo w/3rd row w/o adding the million options it can come with and can carry 1764 lbs as well (IIRC my gross weight sticker).
Thin 34s (below 34.5s and 12 inch width) will still realistically require a suspension lift (a lot of guys run coil spacers for 3-2 inches of lift but I don't like them) via Bilsteins 1.5 (Expy specific shocks), 3 inch (F150 shocks, which fit) front, and 1.5 inc rear(Expy spec) with some minor zip tie-ing, trimming, and some wheel off-set adjustments.
To run true 35x12.5s will require a person significantly more committed.
There are full blown ICON shocks/upper control arms, adjustable to 2.25 inch lifts available as well, and KINGS has something--ALSO (just added this here) there are tire mounted hitch swings and plentiful roof racks (200lb with factory rails, no sunroof).
As always, YMMV and rubbing situations. Wish I had some pics, but still waiting for my kit to get here...