Allowing public share links for private instance

We are installing nextcloud for our small business on an internal server so that it will only be accessible when on our office network (either physically or remotely via VPN). However we occasionally need to share files publicly so we would like to see if we could get share links working publicly.

My though was if we had the instance at nc.example.com Could we configure share links to use a different domain like share.example.com and setup a publicly exposed server for that domain to reverse proxy those request to the nextcloud instance?

Or is there some other way I am not aware of to accomplish this same thing?

Yes i think it is possible. But if you do not really want it because of security reason maybe you can buy an additional Managed Nextcloud only for sharing. You can use e.g. CNAME to map a subdomain of your company to external Managed Nextcloud.