I would be happy to hear of email providers, etc, that also take things as seriously. I can't imagine what hell it would be if someone got access to my email...
[0] https://news.ycombinator.com/item?id=29715989
MarkMonitor is the only registrar that comes to mind but even they have had some incidents and not likely you would just move some personal domains there. They are meant for large organizations.
The rest of them in my experience either aren't a full time registrar (CF/AWS) with odd limitations that change with time or have acquired/merged registrars that have become web2.0 front-ends to old systems they acquired and can barely keep them running. I've tried many registrars in the US and EU and can not find one I have confidence in. Every registrar that has features I like also comes with either stability issues or antiquated technical debt and have lost/let-go much of their technical staff. I am not going to name these registrars because for each of them there will be at least a dozen people here that have had nothing but wonderful experiences with them.
So I guess one could minimize risk by having half of their domains on their first choice and half on the second choice then make sure people know to email them at a domain on each registrar. e.g. Use the second registrar for an email domain that is set as a "backup email" in services that support having two or more email addresses.
I know this does not really answer your question. I do not have a good answer.