yeah take it up with a blackholed email address, while being locked away from public transport and a lot of otherbasic services that's literally needed for life, for saying hard no to literal malware on my phone? I think you're a little backwards.
Just because they haven't told you about the requirements doesn't mean they don't exist. They probably don't support custom ROMs and they didn't tell you because they just assumed you're running the OS that came with the phone.
they don't have any business with my fucking personal phone! where do you live, in the USA? if I only use an old dumb phone, they have no business about it! they can reach me when necessary, and that's all they need to care
Jesus Christ, calm down. They're not "fucking with" your phone by they're asking you to use an app to perform your job duties. And I'd expect any employer to provide you with a suitable phone if you don't want to use your own. Using your own personal phone is just a convenience for you, and having requirements that phone has to meet us perfectly reasonable.