They don't. Not in the US, not in phones[1] or watches[2]. They may have the majority market share in US tablets.
> isn't a monopoly whatsoever?
No, not even if that was true. Monopoly doesn't mean "any company I don't like." You're acting like "Apple isn't a monopoly" means "there's no problems with Apple at all."
Monopoly has a specific meaning. Look it up.
[1] https://www.counterpointresearch.com/us-market-smartphone-sh...
[2] https://www.androidpolice.com/2019/08/15/us-smartwatch-shipm...