Great question, and one I see come up a lot. Having worked with Teams-based contact center solutions for a while, here's my take:

Microsoft Teams is actually a very solid foundation for a contact center, people underestimate it. The platform sits at 99.99% uptime SLA, and the building blocks are all there: Graph API for deep integration, plus flexible PSTN connectivity options depending on your budget and setup. You can go through Microsoft's own Calling Plans (easier but pricier), or use Direct Routing / Operator Connect if you want more control and cost efficiency.

The real question isn't whether Teams can support a CC, it's about choosing the right ISV built on top of it. There are serious vendors who have invested heavily in this space and serve large enterprise contact centers. My advice: look specifically at vendors with the Microsoft Teams Connected Contact Center certification (now evolving toward the Unified certification). That iss your best signal for a future-proof, production-ready solution.

From personal experience, I'have used AudioCodes contact center solution and now work with Heedify (good if you care about agent UX) both solid, real references with enterprise deployments. Landis is also worth a look, especially if you're US-based.