Very concerned for my baby’s development

Ni

My little man is 6 months 10 days today and he still cannot at all sit on his own

I mean he didn’t have as much tummy time in the beginning because of severe reflux

He rolled a few times at 4 month

Now he only rolls in his sleep

He has no interest to sit or roll during the day but if I sit him up he doesn’t mind

Is there anyone else here concerned with how their baby is progressing with milestones?