Totally possible and people do it all the time. After you order a number, we turn it on with forwarding to whatever ring-to number you provide. You can change the forwarding number any time from your NumberBarn account.
A caveat: I wouldn’t use T-Mobile for the forwarding leg to your cell phone, because cell carriers handle toll free traffic poorly. Use any other forwarding provider you want, then have THAT provider forward to your T-Mobile cell. The forwarding provider doesn’t have to be the company that gives you the cell phone, any more than you have to buy the cell phone from the cell carrier.
For long-term forwarding after the initial bridge service, Unitel is a solid pick. For VoIP advice in general, use AI to ask you questions about your business needs and then research the best options. You can’t trust most things you find online, everyone is sending you to someone who pays them.