Sideloading is going to eliminate the small indie dev who could make an honest living through the simple model of 1) make software, 2) let the user buy it once and own.
No subscriptions, no servers required to use. It is very rare now. Apple made this ecosystem it possible by being an intermediary between you and your customers, ensuring they do not run cracked versions of your work to save money and rip you off. It would suck to see it go.
Note who lobbied for this law. Not coincidentally, not the companies that actually did the above (selling software to own), just big corps with competing platforms.
There are three dominant desktop and two mobile operating systems, only 1 out of those 5 is locked down to where even applications are handcuffed. I'm not talking about embedded industrial systems I'm talking about everyday general purpose devices.
iOS is the singular OS in the world where the user's freedom is curtailed in such a heavy handed manner.