Although wikipedia has that as the origin several other internet sources suggested a pagan pre christian origin
https://www.readersdigest.com.au/culture/fascinating-origins-of-everyday-hand-gestures
https://www.mentalfloss.com/article/55702/why-do-we-cross-our-fingers-good-luck
https://www.bbc.co.uk/ideas/videos/why-do-we-cross-our-fingers-for-luck/p06j436j
Noting that these are not proper sources although mental floss links to a text that may be reliable
Mullvad works fine on both LMDE and stock mint fwiw