Is there a way to have a CNAME record in ROS DNS? If not, could that and the ability to add other DNS records be added in the future?
If you mean static records, the answer is no. Only supported are A/AAAA (depending on used IPv4/IPv6 address) and automatically created PTR.
I’ve seen some suggestions in the past to add more types, or other features like forwarders, but no positive response from MikroTik so far.