I don't think this will be possible without developing custom code to send a sales order from ECommerce to Point Of Sales.  

Odoo 18.0 - Failed Workaround 1:
We have attempted to get around this by using the weblink from the POS kiosk for the menu links on the website but the problem so far is it presents a QR code for payment instead of sending the user to the credit card payment screen.

Odoo 18.0 - Failed Workaround 2:
We got around the QR code issue by generating a new bar/restaurant register (w/ QR Code + Online Ordering) and using its online order link and this method captures the credit card payment.  However, there seems to be a caching issue with using the same register online order link as some new sessions will see or access order sessions from other users.

If someone else has experience with successfully using the online link for POS registers or Kiosks for web orders, your input would be greatly appreciated as a workaround to getting website orders to POS orders.