TL:DW - Unless you're training like a Russian Olympic athlete (2+ times per day almost every day), overtraining shouldn't be an issue to think about. That being said, if you find performance decreasing, it can be a sign to give the body a rest.

But what if my gym sessions last about 2-2 hours 15mins everytime? I don't do long rests either, just enough for me to continue with the remaining sets.

Example workouts:
Workout 1(a)
Barbell Squat 6x 1 set each (55,65kg), 6x 5 sets (75kg)
Leg Extension 10x 1 set each (90,130lbs), 10x 3 sets (140lbs)
Leg Curl 10x 1 set (70lbs), 10x 3 sets (90lbs)
Triceps Extension 8x 1 set each (14,18kg), 8x 3 sets (16kg)
Barbell Row 10x 1 set (45kg), 10x 4 sets (57.5kg)
Deadlift 6x 1 set each (75,85,95,100kg), 5x 2 sets (105kg)
Biceps/Hammer Curl, Close-Grip Triceps Circuit

Workout 2(b)
Smith Bench 10x 2 sets (30kg w/o bar), 8x 4 sets (40kg w/o bar)
Incline Dumbbell 8x 2 sets (18kg), 8x 3 sets (20kg)
Incline Dumbbell Fly 8x 2 sets (10,14kg)
Hammer Press 8x1 set (20kg each), 10x 3 sets (15kg each) / Dumbbell Press 8x 2 sets each (22,24kg)
Pectoral Fly 10x 4 sets (90lbs)
Lat Pulldown 9x 4 sets (45kg each)
Hammer Shoulder Row 10x 3 sets (40kg each)
Cable Crossovers & Arms

actually doing too much builds muscle endurance/strength rather than mass. If you are doing heavy sets very often, chances are you are building muscle endurance, which is why you do not feel the soreness the next day.

basically overtraining is mostly about neural (when fried your cns)

on chest day, i train 4 exercise 3 sets each also can feel the doms the day after.

But i dont feel any doms on shoulder day. do you need to do lots of presses or raise ?

side raise x 3 set
front raise x 3 set
seated shoulder press x 3 set
bent over shoulder row (donno exact name. target back for shoulder) x 3 set
machine shoulder press x 3 set
machine back shoulder row x 3 set

hope big shoulder sifuu help me please