I can not find anything about Chrome requirements for Certificate requiring Subject Alternate Names only? Now indeed I think SAN where introduced part of the X.509 V3 certificates specifications but is it a requirement for Chrome?
The issue with creating self-signed certificates using the Webconfig ClearOS app for Chrome could be entirely another problem. I think I also tried to use the app but at the time it was creating X.509 V1 certificates that I had to manually change to be V3, this might not be the case anymore.
This is certainly a complicated subject and I am no expert. Looking at 'Taryck BENSIALI' configuration, a Wildcard DNS within a Subject Alternate Names (SANs) is an approach the I never thought of. Also note Wildcard Certificates can be useful but will only secure a specific subdomain level.