I have done something similar before for issuing tickets for a kids play area. The setup I did was different but I can offer some suggestion as to how you could accomplish this on SambaPOS.
I followed the gift certificate tutorial as a basis
In your case, you would need to customise so you are issuing “tickets” instead of “gift certificates”. You can sell the tickets, which will then print and you can have either a barcode or QR code printed depending on your needs. Each ticket would have an associated entity and account. I would then suggest to modify the way it works to log whether a “ticket” is valid or not based on a custom data value on the “ticket” entity.
You probably also don’t need creation of accounts for each entity since you won’t hold a balance like a gift certificate would and would check validity against your entity custom data value.
Regarding scanning the tickets on entry, is it possible to have a PC or tablet at the entry point with the barcode scanner attached? If so you just need SambaPOS running on that system and it would be relatively straightforward (just checking the “ticket” is valid and if so, setting it as used).
If on the other hand you are looking for a more mobile solution where you are scanning with a mobile device, it would be a lot more work but there is probably a way it could be done, possibly using GraphQL API via a web app. That could possibly also work with a handheld / mobile device with integrated barcode scanner, but if you wanted to use the phone’s camera to scan the code, you will need a third party app or custom app development.
I know this is quite high level but take a look at the tutorial first then let me know if you have further questions.