A venue that takes cash at the counter and orders from a menu has two ways in and one counter. The printed ticket is what keeps them a single queue.
Almost no venue goes to a menu and stops taking money at the counter. Somebody arrives with notes in their hand, somebody else's phone is dead, and a counter that turns them away is refusing sales. So the ordinary state of a bar or a kitchen is two ways in: orders that arrived already paid and are waiting on a name, and people at the lip of the counter wanting to be served now.
What breaks is not the money. It is that each group can see the other being served and neither can see why. The person who ordered from across the ground watches walk-ups get handed drinks; the person at the counter watches staff make things nobody in front of them asked for. Both conclude the counter is unfair, and both are reasoning correctly from what they can see. The decision that prevents it is made once, before doors, and it has two halves: everything that gets made gets a ticket, and tickets are made in the order they printed.
A sale taken verbally and made straight away is invisible to everything else at that counter. It never lands in the station's count, the guest has no name on anything, and whoever is working the printed queue cannot know a sale just went ahead of it. Put the walk-up into the console at the counter so it prints like any other order. It is the same few taps a till would need, and it buys one queue.
Once every sale is a ticket, one rule is left: tickets are made in the order they come off the printer. The pressure runs the other way all night, because the person physically in front of you is the one who can see whether you are helping them. Serving face-first feels like service and quietly kills the menu: a guest who ordered ahead and watched the counter work the crowd learns to come and stand there like everyone else.
Say the rule out loud and put it where people read it. One sentence on the counter, in the same words every time: orders are made in the order they come in, cash or card, and we call your name. Staff need the identical sentence, because the first guest who objects gets answered by whoever is nearest, and five different answers across a venue is the same as no rule.
At close every station should be able to answer one question: how many tickets did we make, and does the money agree. Card sales reconcile themselves because there is a record of each one on both sides. Cash cannot be rebuilt the next morning from anything except what is in the tin, so it gets counted at the counter that took it, against that counter's own tickets, before anybody goes home.