Where did CS6/Encore go?

I'm well aware Adobe Encore is extremely out of date and no longer supported, but it was still great for throwing stuff together. The classic trick to hang onto Encore was to install Premiere Pro CS6 from the creative cloud app, which would bring Encore back with it. Today I tried opening Encore CS6 and I got a popup asking for a Premiere Pro serial number. This never happened before when installing CS6 from the CC app. I fished out my old boxed version of CS6, but could not enter my serial number because it starts with letters, and the popup would not type letters (yes, I am positive it's my serial number and not a redepmtion code. It's a group of 6 with 5 letters, then 4 groups of 4 numbers. This copy was an education edition, which probably has a special serial number they also no longer support yaaaaay).

Regardless, I can't open Encore, can't enter my unicorn of a serial number, and can't even see where the option to retain CS6 is in the creative cloud app anymore. Has Adobe just completely removed the ability to have Premiere CS6 and Encore, even if you're a legitimate owner? Like I said before, I'm well aware Encore is obsolete and unsupported, I'm really not interested. I'm just perplexed why software I have legitimately installed suddenly refuses to open and pretends I don't own it.