Good news I don't think it would be super tough for us since we're built using pretty boring tech (i.e. not a lot of dependencies on a particular cloud vendor), don't have a bajillion microservices, etc.
If you haven't seen a lot of demand for a self-hosted version, you might have beem asking the wrong people. Non-cloud advocates and companies with regulatory on-prem requirements tend to not be the loudest in the room for a myriad of reasons.
It's also unpopular and thus a waste of time to argue for self-hosted solutions in a room (or world) full of cloud-first evangelists with dollar-signs in their eyes.
It's just the fashion right now and fashions rarely care about being practical or affordable or safe for the average person, let alone any edge cases.
Why I am saying this: I want to strongly encourage you (and any software vendor really) to build and offer an affordable self-hosted version of your software. The demand is there, believe me, and if word spreads that your solution is a viable on-prem solution, interested parties will come out of the woodwork, you can be sure of that.
On-prem users tend to think more long-term because they (have to) invest more manpower, organizational knowledge and hardware into an on-prem deployment. So they tend to be less fickle and flighty than cloud customers and think long and hard before selecting a solution. However, as a result they tend to be loyal long-term customers and and such can be worth a dozen or more cloud-based customers. Might be worth considering.
Personally, we've planned to move away from Jira before 2022 exactly because of Atlassian's decisions to in effect kill its on-prem versions (by pricing them out of range for everyone but large enterprises customers with money to burn). So I can guarantee that Kitemaker will get a fair consideration (I just saved your page) if it offers an attractively priced on-prem edition before 2022 :-)
Good luck with your product, I do agree that it looks very slick and I will continue to watch with interest.
They often have regulatory, privacy, or security issues that require on-prem solutions. Even if one can get some sort of certification regarding those issues for a cloud solution, it may not be universal and can make things much more difficult to confirm that the cloud solution meets their regulatory, privacy, or security requirements.
That being said, maybe it's an interesting way for us to stand out from the crowd.
And this HN launch has given us a lot to think about in terms of self hosting!