There's no, like, gun to your head saying you HAVE to side load apps. You can just... not... do that. If you think side loading is insecure. You can download 100% of your apps from the play store. In fact, that's what 95% of people do.
I mean, what's the threat model here? That you somehow forget your own belief about side loading being insecure and then accidently side load an app? Does that even seem possible?
I can kind of understand this argument for granny who doesn't know where she is. Kind of. But for you, it makes no sense. I mean really, think about what you're saying here about you as a computer user or even as a person.