Yeah it's all about how you configure the system (for example a lot of linux distros are insecure by default, how many of them have secure boot support, selinux/apparmor, ACLs out of the box?), but still the base was not designed with security in mind years ago, so the best would always be to design something new (just think about xorg vs wayland), but it's a huge task and really difficult to have something like that be developed in a complete foss manner (I mean in the linux spece there is red hat that is mainly pushing new security standards, selinux and the likes), I am not saying those are the best, but still they are something, but it all feels like a patch on top of something with a lot of holes 😅.

But yeah, android on top of linux could be better than native linux apps, bur at what cost? Batter, performance... It's a difficult world.