American League:
East Coast:
Yankees, Red Sox, Orioles, Rays
Great Lakes:
Blue Jays, Tigers, Guardians, White Sox
Midwest:
Twins, Royals, Astros, Rangers
Pacific Coast:
Angels, Mariners, Athletics, expansion team (Salt Lake City or Portland)
National League:
East Coast:
Mets, Phillies, Nationals, Marlins
Great Lakes:
Pirates, Brewers, Cubs, Reds
Midwest:
Cardinals, Braves, Rockies, expansion team (Nashville)
Pacific Coast:
Dodgers, Padres, Giants, D'Backs
Meh, just off the top of my head if they went to 4 divisions. You might be able to reshuffle some AL and NL teams.