You apparently got hold of the best mid-2012 Macbook Pro! I understand why you don't want to let it go ;-)
I only use the Thunderbolt connector for connecting it to a TV (for watching videos etc.).
Regarding Adobe apps: I use Photoshop CS4 now and then (the main reason I don't want to upgrade to 10.15 Catalina, but still wanted to get Logic Pro which was frustrating to see needed that OS to work. So I'm very glad I finally got to buy it WITHOUT having to upgrade my OS!). Anyway, Photoshop CS4 works fine within 10.12 High Sierra. The key to making it work, as far as I remember, is to install it on an earlier OS which is compatible. If I remember correctly I installed it on OSX 10.9.5 (Mavericks), then upgraded the OS to 10.12 (High Sierra). Might be worth trying with CS5 as well.
Like you I also looked into Affinity and after checking their trial version (and finding out that it does indeed work in much the same way as Photoshop and can be configured for a similar look and feel) I bought their Affinity Photo app when it was on a 50% sale a while back (luckily for those who haven't bought it yet, but want to (or their other apps) they currently have a 50% sale again). I haven't yet had the time to learn the new workflows, so it's still Photoshop for me, but when I do I can probably switch completely stop worrying about 32-bit support in MacOS.
Sorry to everybody else for the off-topic discussions. I was hoping for a "Private message" option here as usually found in other forums, but it doesn't seem possible.
Thanks again for all the help with making it possible for me to buy Logic Pro even when I use an older OS version. Looks like a great app, and with similarities to Garageband I think I'll be getting the hang of using it soon (although I will be looking for some "getting started" youtube videos or something).