Need secure folder

Secure Folder requires Knox which is a both hardware & software based security and F41 doesn't have that hardware so it can't be provided through software update.

And for App lock "S Secure" is already there.

You may be right at your place, but as with price and policies, F and M series lacks some special apps like secure folder, goodlock apps, etc., then comes to A Series which comes with all these features with higher price, and then finally comes to S and Note Series, with higher price having access to more advanced features like diff edge lighting effects, etc and now from s21, S series are also compatible to S Pens
So, if Samsung give apps and some features access to F and M series as A series, It will increase the price as well. As Samsung is providing phones(Like F and M series) in lower and affordable prices to its customers who don't like customization or can't afford expensive phones or need a good phone in affordable price, that's why Some features lacks! 😀 👍
I hope you Understand and Liked it. ✌
Regards
Anant Gupta