Thermostat wiring in need of fixing

I am trying to install a new smart thermostat and the control wire is not working (it controlled the heat fine in the winter.)

I came out to my air handler and this is the wiring I’m looking at and need help.

Can anyone tell me if this is worth trying to do my self or should I call?

file:///var/mobile/Library/SMS/Attachments/a4/04/BF222EFD-41B6-4DB4-A4EE-3B96FBC9FD12/63908660703__420E202F-1BAB-46B6-99D2-36C7959E96E9.HEIC