This idea was inspired by the Driveatars in Forza. I know this is a 6 year old game so this may be an idea for Sea of Thieves 2.
My thinking is the game can learn how you play, like how many shots you take on player ships then average it out over time. For example say you played 40 hours in a month and of that time you were in player combat for 10 of those hours. The game could register that you were in combat for 25% of the time.
Now when you start the game and join a server the game could try to put you with other 25% players. This would also apply to players who avoid combat so their percent would be something like 5%, so the game would try to pool similar play styles together. The server weight would be the total player percent averaged out, for example, 12 players on the server could average 17% and a new crew joins with a average of 40%. The game could look for a server closer to the 40% rather than the 17%.
I don't know how many servers there are so I'm not saying a 75% player could never be on a 5% server, but at least trying to pool similar players would increase combat for players looking for combat and it would pool players looking to just sail the seas so there would be less grievance getting sunk when you just want to sail.