After Google ditched Domains I moved to Route53. I guess the only downside is that it doesn't handle some TLDs?

What you want from a registrar is to keep existing for many years and resilience to social engineering, and AWS seems like the next best thing to Google which you famously can't even talk to for a social engineering attempt. I expect AWS account management to be almost as good as Gaia, but don't really know how hard social engineering is.