Wireless Barcode Scanner 

For the Credit Card Terminals: 

I recommend the Pax A35 for most in store setups, as they are cost effective and have good stands if you want to mount them. Wifi & Ethernet connector

but we can also use the A77 (mobile device, wifi and 4g LTE)

Or 920 (battery, but bigger then A77, WiFi only)

Actual POS Computer:

You can technically use anything you want here as long as it runs a browser. I've used a regular PC, but then used a touch screen with a vesa mount (something like this: https://amzn.to/4b9TvWM)

Or my other favorite is to use a large Android Tablet. Something like the Samsung Galaxy Tab s11 Ultra https://amzn.to/4sOwkaB

One nice thing about Odoo is it is fairly hardware agnostic. You can use about anything, the only part it gets a big picky is on the receipt printers when using a tablet.