Do you absolutely require linux? If so something like a older microsoft surface would be best probably. Where its a full computer x86 based and has a detatchable keyboard, or a 2-in-1 that folds the keyboard back. Downside with this is worse battery life, and itll be a bit bulkier.

If what you want is just a tablet that does not spy on you id actually reccomend just getting a pixel tablet and putting graphene OS on it. Its a custom android ROM that strips a lot out and sandboxes things to give you more control over the device while still being based on android and bringing the advantages that has (battery life, mobile optimization, etc). Down side is you dont get the full Linux OS youd want.