They would just need to release a pro version of their app you can pay upfront in the App Store, and then release paid updates later following the same model. No need to "turn a company" into anything.
How? Paid updates are not possible with the app store. If they were we wouldn't have to jump through those anti-user IAP and subscription hoops.
As for "littering" Apple's app store, it's just rows in a database, of which there are millions. Waste sucks, but we're not talking about a meaningful amount here.
Platform gatekeepers in 2023 should simply vet third-party app stores and award them a Certificate once they pass anti-Fraud. The hardware itself should otherwise run open source firmware that only enforces UL/FCC certification requirements and basic UI standards (be they audio, video, or network). If Apple wants to go beyond that, they can setup Claris or something with its own such Certificate to compete with Amazon and all the other potential third-party ecosystems. This hunk of garbage may look ridiculous, but cast it in an Al custom NC enclosure with miniLED and an m2ultra and… https://www.worthpoint.com/worthopedia/brother-geobook-nb-80...