U already have a notes option for each workout but it would be nice if u had a small notes option / comment option next to each exercise as well . For examplE :
Shoulder press : weight went up but slight pressure on spine .
Squat : good set but last set used a belt .
These things we forget at the end of the workout .

There is a note section to make comments, but they need to fix it so the comments stay and you can go back and read the comments or update them.

If you add a note to a workout, you should carry it over to the next workout so if you have made recommendations for an exercise, you can see them.

Yes! Perhaps also include a box for "perceived effort (from 1-10, with 10 being unable to complete prescribed exercise). Very helpful for tracking fatigue across sets and knowing when an exercise is becoming too easy.

Add a note for the exercises such as "used Dumbbells instead of KB because...." Or "all squat racks taken, did hack squat instead" so I can remember and my trainer can see why the weight was different or what issues I am having etc.

I agree! Things also like 12 push-ups was really 8 regular and 4 from knees so you could improve next workout.

For times when you can't finish a set at a weight n you need to go back, or when the weight is too light and you want to increase weight for last few reps.