I think one of the best things the Ymaryn can do right now would be to reestablish the International Games, especially the Artisan Games, and invite everybody. This will help with so many things, and give us opportunities beside that.
First up, we're behind technologically. Artisan Games allow us to share innovation with everybody, so that issue quietly dies. And with our production capabilities, being on equal technological footing means we're ahead.
Next, we don't like colonialism. Well, the same innovation sharing that helps us will also help everybody who is being colonialised. Taking over a country becomes a lot harder when the locals aren't two or three tech levels behind. This allows us to stop Vortug without direction opposing them. We can do it while being friendly with them if we want. Better than that, it means that Vortug themselves will inadvertently help bring their victims up to date with technology so that they can better oppose the Vortug.
But maybe you think that Vortug doesn't want to join these games if they have these consequences. Well, the brilliant part of the Artisan Games are that they self-policing once they have momentum. You share innovation. Once there are enough people in the games, that will out-innovate anybody else. So if you aren't in the Games, you fall behind. It also keeps people from leaving the International Games, for the same reason.
And Ymaryn is traditionally the host of the Games. Doing this would reaffirm us as the successor state of Old Ymarym, which helps with the greater Ymar project.
Not to mention the tourism and prestige that being the host of the game will bring. Tourism which provides a convenient vector to infect the entire world with our culture - oh, hey, that should help against slavery. Unlike RL, we don't need to switch hosts and share those benefits, we can get them every time. And of course the costs for building appropriate facilities and infrastructure to host such Games will only be necessary once, after that it's just maintenance. So it will be a lot cheaper than having it in a different place each time as well.
Next up, we would be the host and get to choose who to invite to the Games. Effectively we get to decide who is a country in the public eye. I'm not talking about the big ones that are obvious, but the edge cases. Provinces, vassals and colonies that want to break free... are they considered their own nation or not? What about loosely tied together minor kingdoms? Is a personal union two countries or one? There are lots of subtle decisions. And sure, there may be official statements by other great nations about who they think is a country. But who reads those? The International Games are inherently entertainment. They generate attention. If somebody is invited to the Games, the public will consider them a country, and such pervasive attitudes tend to have longterm effects.
So there are plenty of benefits. Yet is this possible? The costs would mostly be diplomatic, ensuring that as many countries as possible show up - preferably everybody. But we have been focusing on diplomacy for a while now. Yes, it was only lightning rounds, but those covered a lot of time. So in universe this has been a longterm focus. And we have diplo heroes. And other than diplomacy the cost is just infrastructure which we should have no problem building.
And while we're at it, let's add Scholar Games (updated version of proposed Clerk Games), because why not.