If game has a big community and a lot of players it is more simple to sell in-game NFTs inside ecosystem of the project.
Very often NFT is possible to buy and sell only on the platforms marketplace. They do not sell NFT on other marketplaces.
That is why the liquidity of the ingame NFTs are not very high.
The most important thing for every game with NFT is to develop their community and increase the number of users to increase their liquidity and develop an ecosystem.
Now there is a big competition between different games and it is really very difficult to build a community.
It is very important to work and it is necessary to check what has already been done.