How big is your play area?
There's a soft play cafe locally, and it can get quite busy:
There is a small play area, and a large cafe areas
(small play area is a tiny soft play for babies, then bigger soft play with 1 closed slide, 2 open slides, a ball pit..., things to climb, a tunnel upstairs...)
Under 12 months are free, 12 to 18 months £1, 18 months pay around £3.95, up to 5 pay £5 (not sure exact amounts to be fair). Children over 6 are not allowed in the (small) play area - but of course can stay in the cafe, parents don't pay to come in.
I think the place makes money mainly with organising birthday parties every Saturday and Sunday. If they are not booked then, they open to the public, but that rarely happen, so they are obviously popular.
They can charge this amount because there is not much else locally, and mums are happy to go in, have a coffee whilst the kids burn some energy.
Lunch times are very busy, sunny days are dead (so it's lovely to bring a tiny one!), and afternoon quiet.
Don't forget that many mums would love to come often, but simply cannot afford it. This sort of shop struggle, and is rarely sustainable in a city centre where the rents are very high.
Good luck!