So you have no opinion on the Toyota Tundra?the problem when you ask a question like which brand is better, you will get answers slanted towards that persons preference.
myself, i could care less what nameplate hangs on the hood, i've owned and driven all 3 (gm, ford, dodge)
by far the worst for reliabilty i've seen with my own eyes is ford super duty diesels. my dad's construction company was in business for 42 yrs. From '79 till the late '90's, it was all GM gasser trucks, was not uncommon to see 300 thou with no major probs. then in '98 he got smitten by the SD's torque, went hardcore on ford and bought approx 17 or 18 diesel SD's. the only good engine they used was the Navistar 7.3, the 6.0, 6.4 and 6.7 were strait up garbage.
turbo failures galore, prob a record, five turbo's on 1 truck, HPFR and HPOP failures were every second week. injectors dumping diesel into the crank was another huge prob and ford never could seem to figure how to seal up the oil pump on any of their diesels. pretty bad when we show up at a customers house and have to throw a piece of cardboard under your new truck so it don't stain the customers driveway. and yes, multiple times ford had to take the cab off to work on them which is RIDICULOUS!!!
after close to 20 yrs with ford, he got fed up and bought a 2020 ram 3500 diesel. unfortunately he died 6 months after buying it, so i have no say on it's long term reliabilty
Ford gasser motors don't fare much better in my eyes either, especially when my sister takes her windstar in for normal servicing and gets a $3800 bill after 3 spark plugs snapped off...
my current employer has about 30 trucks, which were split pretty even between ford and gm trucks and a bunch of sprinter vans. as the fleet aged, more probs occurred. the gm's were famous for chucking codes, i don't think a single one didn't have the check engine light on, but they still ran like a raped ape, and the fords-well they were catastrophic failures-like a t-case breaking right down the center of the case on the highway at 60 mph then skidding all over the road trying to come to a stop. and the sprinters were electrical nightmares and we bent the trailing axle on 3 of them very easily.
earlier this yr he got a new fleet of new 1 ton gm's (22 trucks) and some new fiat doblo vans (8). the only ford left in the fleet is a 2019 F450 flatdeck which has had no serious probs yet.
imho if you want LONG TERM reliabilty, sometimes you have to go back in time. in my experience, most truck from the '90's down will prob go further and longer than most new trucks. my '90 gm has 400 thou and the block has NEVER been cracked open. sure, did the valve seals at 200, and an intake gasket, but thats it, which is pretty minor. a gm 350 is just about one of the most bulletproof engines made- hell, there is more non gm vehicles that have a small block swapped in them than all other brands combined. not unusual to find them in fords, chrycos, imports, boats, even planes
and for service and price-tuff to beat a gm. basiclly 2 engines, small and big blocks, with unlimited interchangeability, compare that to a ford or chryco motor, 5, 6, 7 or more blocks with no interchangeability, now imagine the tooling costs to make parts for all those motors. to build a 500 hp chev, if it was to cost $2500, that same 500hp in a ford would be $4000 and a 500hp mopar would be in the 6 grand range.
as far as i'm concerned, the last great reliable motors were chev 5.7's, chryco slant six'ers and ford 351 C's. the new motors don't even compare. would also give honorable mention to the gm 396, it's a monster of a mill.
for the utmost in reliabilty, you can't go wrong with a gm squarebody or an older dodge W truck