Chess App is a free and powerful PGN analyzer. Upload a game and get move-by-move engine evaluation with no login and no account required.
A lot of people are fine with getting a free service knowing the company offering the free service spies on them, harvests data about their life and sells it to advertisers and marketers.
I'm not fine with that. When I build an app, I build it thinking about data security and privacy at the beginning, in the middle and at the end of the project build.
Chess games you submit to be reviewed and analyzed stay on your device. Playing chess, your data is saved in a central database, but it is just whatever username you use and the chess moves.