https://docs.cloudron.io/domains/#overview 😉
Yes, you can add new domains to Cloudron. Depending on where the authoritative servers are for the domain, you can use the dedicated API-based setups (i.e. AWS, DO, Namecheap, Linode, etc), or you can instead use the Wildcard setup for any other service that's not explicitly listed in the providers list.
Then once the domain is added to Cloudron, you can add redirections to the same app if you desire, in the App page: https://docs.cloudron.io/apps/#redirections