“I guess NATO can’t expand any farther eastward.”
The nation of Georgia is a potential NATO member. So is Moldova. Armenia is playing nice with NATO lately and might be in play in the next decade or so.
NATO needs to be dissolved shut down and replaced with as many as three (or four) geographically focused defensive alliances. Which we don’t have to be a member of any of them. Some we could just have observer status like Sweden did with NATO.