The answer is - probably not.
CGNAT is very tough for standard SIP NAT traversal because all inbound ports are closed and the IP addresses are very often rotated.
Some carriers that use CGNAT may have special SIP gateways (proxies) and in most cases those serve their own SIP services, which I doubt Starlink has.
I saw that Starlink has "Public IP" option. This should provide you with proper public IP address, which should be usable for SIP.