If AMD has as much trouble as it does just getting customers to switch from INTEL then this new entry will have a really hard time if they expect to get to become commercially feasible. "Its long way to the top if ya wanna Rock n Roll".
Agreed, ARM faces massive challenges for mass deployment. Ripping and replacing all your code is no small task, but it was certainly a lot more attractive before an x86 alternative (EPYC) came along. EPYC is really sucking the oxygen out of the ARM data center conversation. Ampere's coming in a bit below expectations, and Nuvia is a bit too far off to really matter much right now. Graviton2 is interesting, but spurious benchmarks and indirect comparisons do little to tell us of the actual worth of the platform. I'm of the mind that Amazon is probably carving these out for cloud customers at a loss, just to enable the platform. It wouldn't be the first time AWS took that tact. In fact, it's been the business model forever.
In short, I think we're a long way from ARM being a major player in the data center.