Now Reddit are coming for the individual personal subreddits

In fact they did not, because I have two subs for which I was the only mod and user. The one that had been long closed and private got no attention, only the other dead sub where I'd closed it quite recently in solidarity. There's no functional difference between the two, and no benefit to anyone to force the one to be reopened and not the other.

I can confirm. /r/MKaTS is a longstanding private sub of mine. No modmail (yet).

There's also /r/MKaTH, affiliated with the former but public. I'd taken that private and added a solidarity note. So far, no modmail, though it has far fewer members than /r/dredmorbius.

(OP, FYI.)