Yeah typically at my store it’s at the very least doing dto (taking the orders) and handing them off/taking the money at the window. Depending on the time it can also be making the drive thru drinks. For me we use this right at open when we only have two baristas while the shift is doing all the opening tasks (pulls/putting away orders/putting in the order). We also sometimes use this after our morning peak when we have fewer people on the floor. But we call it solo DT or saying you’re doing all of drive.

I believe solo DT refers to being DTR / DTO /and DT bar, so you'd be doing all the the drive thru everything. In my store this happens towards the end of a closing shift when people have gone home and it's gotten slow, with anyone else left in the store ready to jump in and help if there's a mini-rush.

I've never heard anyone in my store say solo drive though. They just say "double" and then I'm always confused whether they mean just DTR and DTO or those plus bar.

We call solo drive DTR/DTO and sometimes it includes bar for drive thru (like when we open and it’s dead)

I think it depends on each store because at my store it means: take/input an order, grab food items that go with the order, and cash them out.
But I have worked at a store where it was: take/input the order, make their drink, get their food, aaand cash them out.

What soloing normally means for me is taking the orders, doing the window and putting together stuff people order at the window (when it’s busy).