Can I pair a standalone Apple watch to an iPhone without a cellular plan?

My iPhone service is through Xfinity. I would like to get a standalone Apple watch for my 9yr old daughter (who does not have a cellphone), but Xfinity doesn't offer a standalone watch option. If I pair an Apple watch on their network, it will be connected to my phone number and she will receive all of my texts, etc., which I do NOT want.

T-Mobile DOES offer a standalone option, so I could get a standalone data plan for her there, but it still has to be paired to an iPhone (which again Xfinity will not allow). My question is.. can I pair an Apple watch to a phone that doesn't have a cellular plan? I've received conflicting information about whether this is possible. Since the actual data plan is specific to the watch and provided by T-Mobile, I can see how it might be a possibility. I'd use an old iPhone 11, but it would just sit at my house plugged in and on a Wifi network. We aren't ready to get her a phone, but do really like the idea of her having a watch. I am hoping someone has experience with this scenario and can provide some feedback. Thanks!

**And just to confirm, I can't switch my phone to T-Mobile for another year because we have a year left on our contract.