I would like to demonstrate through the following screenshot that you can add more than 2 domains to Virtualmin.
As you can see, I have multiple virtual servers (domains) running on one instance of my Virtualmin server. This is a feature which is available in older versions though you should upgrade to the latest version for the other enhancements that one gets with updated software.
Virtualmin has a community of helpful, experienced and knowledgeable people. If you, @sherlockholmes, ask questions about how a certain goal can be achieved rather than attempt to run down Virtualmin due to your lack of progress caused by your own ignorance and inability to unlearn whatever it is that some other web hosting panel may have taught you, we will all get along better and make progress faster. For example, I had to spend time and energy in creating and sending you this screenshot to demonstrate how Virtualmin looks when it is configured to host multiple virtual servers - and I did this to refute your, well, absurd assertion that Virtualmin has a two domain limit.
My time and energy would have been much better spent in pointing out to you how to correctly configure nameservers in your Hostinger control panel and how to use Virtualmin -> Create Virtual Server to create domains and subdomains which can be hosted in potentially unlimited number on Virtualmin.
Shall we try again by creating a new topic, telling us what are the exact steps you have taken thus far on the legacy system which you appear to have inherited, and what is it that you wish to achieve immediately?