How are health and safety standards irrelevant to product features?

Better question: how are they at all relevant? The health and safety regulations are proscriptive: you must not harm consumers. On the other hand, product features are creative expression. It would be like the government telling you that your novel must include at least three references to other writers' works.

Anti-trust is about anti-competitive practices and consumer benefit. Carterfone and Microsoft are possibly the most relevant examples. Google and Apple are a duopoly in the phone market, and Apple's (and Google's in the case of Epic) behaviour towards these companies could be seen as anti-competitive.

If you want to run a platform business, you'll need to be mindful of anti-trust law more than anything else. The Apple platform is perfectly capable of anti-competitive behaviour given it's market share, and doubly so given Apple and Google control 99% of the phone market.