Adobe, without warning disabled my CS6. I have receipts and have registered it since I bought it. And there response was too bad, so sad. Upgrade.
I started using the Affinity apps, three and as stated, they are similar, but different enough to have a decent learning curve. That said I really like the apps and the company. $55 each, and if you pay attention they knock a third off once or twice a year.
While but as cram full as the three Adobe apps (Illustrator, Photoshop and InDesign), they are constantly improving and adding features. And more importantly, are very receptive to user feedback and issues.
If you are dead set on CS6, check the OS compatibility issues. While they will work with Mojave, there will be issues. I ran CS6 on a 2013 Mac Pro with Sierra, and while it worked I could never get the fonts to display in the menu properly. One or two other small issues, but nothing awful, just inconvenient. As you go to High Sierra, Mojave the issues are more pronounced and a few more present. Again check the list.
You can get a nice 2015 (2017 if you really pay attention( or older MacBook Pro or iMac for around $500 or less. Add an ssd or two (they are crazy cheap right now ($75-95) and some memory, (memory first) and you have a dedicated graphics workstation, that will also do your daily driving chores.