Looking for Photoshop v21 or older

Hi! I'm running on mac OS Big Sur (version 11.7.10) and due to my laptop's age, I'm not able to update the OS any further. The oldest version of Photoshop available on the CC desktop app is v22.2, which is not compatible with my laptop. I need at least version 12.

Does anyone know where/how I can download a version of Photoshop that is older than v22? I've looked on https://prodesigntools.com/ which directed me to Adobe's customer service, who basically told me they cannot help me and that I need to update my mac. Any help is appreciated!