I live in Eastern Europe. After launching Server Meshing, will I be able to play with friends from the USA?

We do not plan to limit what shard and region a player can choose.

A player will be free to choose any region to play in and, within this region, we will allow limited shard selection. For example, the shard with your friends or the shard you last played on.

Since all player data is stored in the global database, players can switch between shards similarly to how they can switch between instances today. Items that are stowed will transfer with the player and are always accessible regardless of shard.