Here is the Payne PY3P installation manual. This should help in locating the common connection.

Page 17 of the manual shows a splice box which is meant to connect to the thermostat. It shows the common as a brown wire. Here is capture of the details from page 17:

I see thermostat wire coming in on the bottom right. Find what the brown connects to. It looks like a mess :\ Orange uncapped, blue hooked to white instead of the unused white.

That could be cleaned up for sure. Use the white wire for the white, cap off the unused orange and blue. Connect black to the brown to get your common as the black. Cant see the rest.

Only real risk is hooking up AC incorrectly. Dont put the white coming from the AC to the white at the board, that is meant for heat. Put the white from the AC to the yellow at the board.

https://smartthermostatguide.com/thermostat-c-wire-explained/

There are no standards for wire color! Any wire can be used for any purpose. A previous owner or handyman may have been “creative”, so what you find behind your thermostat might vary from what you read about online

Here are common uses for wire colors:

• Blue or Black – C – Common wire, may be unused by your existing thermostat. Enables continuous power flow from the Red wire.
• Red – R – 24VAC power from the furnace’s transformer
• Red – Rc – 24VAC (dedicated to heat call)
• Red – Rc – 24VAC (dedicated to cooling call)
• Green – G – Fan
• White – W – Heat
• Yellow – Y – Air conditioner