When I moved into the Granny flat when DGS was born a lot of my friends (not Grandparents) told me I would be 'used'.
Not the case, I chose to move here, it was only at the beginning of lockdown that DD started working outside the home.
She and I with SILs diary sit down at the beginning of each month and check dates DGS and I do a lot together and sometimes that conflicts with DDs dates so we work around it.
I had problems with SIL a couple of years after I moved here, not using me, but being jealous as his Mother died many years ago and he was upset that I was with DGS and she is not.
All sorted out now, he can still be difficult but that's just him and not aimed at me.
I still get remarks from non-grandparent friends but I put that down more to a touch of the green eyes when they see how much fun I have than anything else.