Is there a way to join pacers without having to log off after a warm up
Unfortunately that is not a current option. At current the only way to ride with a pace partner is to select them from the game startup OR to catch them on the open road and self navigate to follow them.
I have had problems switching between the bots. Takes a while to log out and reenter but frequently upon re-entry, it does not put me in the peleton with the bot but instead I end up on my own