Good that you got things working using the direct IP rather than the broadcast discovery.
A possible alternative that might work for discovery of your printer is the addon mDNS Repeater, which I saw mentioned in the following post
https://community.ipfire.org/t/see-google-nest-on-blue-subnet-from-the-green-subnet/9539/3
Where the poster was interested in broadcast access from green to blue for smart thermostats.
I am not certain enough to say it will help your use case but it might be worth a try as according to the wiki page on the addon it requires very little configuration. Just the definition of the two subnets involved.
You know the printer can be accessed via the specific IP so it might be worth a quick test with the addon to see if that helps with the discovery process for the printer. If it does, then it would be good to mention that as a use case in the mDNS addon wiki page.