I've noted that I have some knives were the design of the sheath for retention, retains the knife against reasonable attempts to use it. I got a Glock knife for SO-ing a GSSF match. The accompanying sheath was difficult to use, unless I am missing the magic manipulation. I shaved off some plastic to fix it. Now it won't hold the knife if upside down but since it is a freebie - so what. Another is a 5.11 knife I got at a deep discount. That sheath is impossible. It take considerable effort and a push at the right magic spot to free the knife. I can't do it left handed at all. This is it -
https://lapolicegear.com/511-51119.html
It is going into the box of things which you bought and ...