Got my mini a couple weeks back and bought a few things like you are planning to do. I got the UAG case and bought two different tempered glass screen protectors, one a mattered the other one normal.

Here's the case: [U] by UAG Designed for iPad Mini... https://www.amazon.com/dp/B09G846D72?ref=ppx_pop_mob_ap_share

Matte screen protector: amFilm 2-Pack PAPERed Glass... https://www.amazon.com/dp/B09FK3QM78?ref=ppx_pop_mob_ap_share

And the regular glass protector: Spigen Tempered Glass Screen... https://www.amazon.com/dp/B09GGC6TD6?ref=ppx_pop_mob_ap_share

Haven't used the Spigen protector yet but I do have the same on my iPhone 13. Loving the matte so much right now, especially with the Apple pencil I bought to go with it.