That depends on how confident an answer you want. Purism has certainly talked about this and at one stage plans were more definite than they have been in the last several years while the focus has mainly been on the Librem 5. I would be surprised if a tablet is not somewhere in Purism’s thinking but I don’t speak for Purism and I doubt Purism will want to comment publicly because a comment will be interpreted as a commitment.
From a position of self-interest, I would rather that Purism continue to focus on filling in the gaps in the Librem 5 - and then use that as the launching pad for a tablet, basically based on the same hardware. Various topics already contain rampant customer speculation on this subject.
What screen diagonal did you want? You can always use Librem 5 with an external (portable) monitor, including but not limited to the NexDock, to get an approximation of a tablet.
I don’t know how many tablets are x86-based and hence how many have the ME problem (per your topic title). Most tablets in the market do however have the spyware problem i.e. run iOS or Android.