Please help me understand Made For iPhone hearing aids

my audiologist has suggested that, to maximise my environmental awareness and to help with my tinnitus, that I should get hearing aids. I believe a few of you use them and was hoping you could help me. I'll be getting these on the UK's NHS so there is a certain limitation to the devices I can have but, having looked at what they do offer, I understand that classic bluetooth devices are a no go with voiceover and that to get an acceptable latency we need bluetooth LE or devices that are Apple MFI certified. I think the alternative they might be able to offer, should I make my argument plainly enough, is an Oticon device, though I don't' know which model. Are these any good? With Siri getting an overhaul in 27, I was wondering how it worked with hearing aids. Is it the same as with AirPods in that I can start a request by saying Siri and the microphones on the hearing aids pick that up? Also, how does it work for phone calls? Presumably I can't hold the phone up to my ear as that will cause feedback. If anyone would be kind enough to step in and explain how hearing aids work for a voiceover user, what advantages they might have, what drawbacks compared with something like AirPods, that will be fantastic. Final bonus question: Music, as I'm sure it is for many of us, is pretty important to me. Music piped through hearing aids, or at least the ones I'll be getting with the little tweeter like speaker floating in the ear canal, will not be great. How do you get high fidelity? Is it a case of taking off the hearing aids and switching to something else, maybe AirPods or alike that have been tuned to our specific hearing loss? Thank you.