SMS has somewhere to go in between the sender and recipient. Where does this go if I send a message then go offline before the recipient comes online?

It seems like both parties must be online at the same time for the message to be sent. My understanding is that your message will wait on your device until the recipient is online and then will be sent, so if neither party is ever online at the same time, it won’t work.

OP says they have a tool changer, so filament mixing isn’t an issue.