Mitsubishi only advantage is the 4x4 mode seems more famous/durable as they race a lot in Dakar race with their 4x4 technology.

Hailat really a let down nowadays, if not because of Toyota brand i think it is worse in the lot (Besides from reliable, everything from comfort to safety features is not the best), Dmax at least the 1.9L engine really fuel efficient, but not really powerful. In Japan, Isuzu is famous for making small diesel engine for trucks & pick-up. 

Pickup Brands famous for

Mitsubishi - 4x4
Toyota - Reliable
Isuzu - Fuel efficient
Mazda - Another rebadge Isuzu
Nissan - independent rear suspension system

what to choose for comfort ride, no offroad?

If base on today market with high diesel price, 1st choice would be Isuzu D-Max.
Wait for new Isuzu D-Max with new 2.2 DDi MaxForce engine.

Their on-road comfort is good and i have seated in 1 before (2nd Generation, 3.0T) in the rear seats from Kulim to Kuantan without any discomfort along the way.

just test drive Triton Athlete today. comfort feel like drive SUV, cabin not much sound diesel. turbo sounds angry at low speed like asking me to go faster, highway 150 no wind sound like CX5 2015. going to test Dmax Ranger Navara Hilux later.

Front seats most pick-up also quite similar, the rear seats are the one more important to know if it is comfort or not.
Pick up family members seat behind and listen to their feedback.

I've heard nissan wildtrak backseat seems one of comfortable 🤔🔥

A friend of mine told me since he owned one 😐🔥

Nissan pick up rear comfort is due to muiltilink suspension (Competitors using leaf springs), but sadly the engine side is not the best.
A lot of mechanic feedback their diesel engine is more fragile (easy to crack on the head/valve area) not the best around competitors for durability.
If you can accept the weakness, Nissan Navara is also a good option for comfort bias pick-up.

Front seats most pick-up also quite similar, the rear seats are the one more important to know if it is comfort or not.
Pick up family members seat behind and listen to their feedback.

done test drive back seat

comfort is Ranger WildTrak > Ranger Raptor > Triton Athlete > Navara VL > DMax XTerrain

personally i like Triton, DMax is bumpy idk how you like it.