That's one of the perils of putting to many of your eggs in one basket. I don't understand the iMessages Facetime thing though. Perhaps it's peculiar to the U.S. market? Most other countries make good use of WhatsApp Skype etc. for their messaging and video needs, or even Google's own 'messages' app.
Surely you could Airplay to your HomePod using your iPad?
Definitely there is a myth creation wrt the ecosystem red herring though Apple does integrate it's products well and seamlessly which is also my major concern investing in this ecosystem. But I also used iPhones until 7+, also paid for Apps, iCloud storage etc...but I don't face any showstopper situation when I keep switching to Android and iOS pretty frequently and consistently...
Apple watch and HomePod has very tight integration with Apple iOS ecosystem which is why I don't buy it in addition to its cost.
iMessages is only for people having iPhones and I can't ask my contacts to buy iPhones hence it is unpopular in our region. Otherwise, all Apps (Office 365, password wallets etc) are available in both platforms and in Android it functions better in some cases.
I use Gmail and Outlook app for emails, Chrome and Edge for browsing, MS Office works neatly, WhatsApp, Telegram, Facebook, Travel Apps, Banking App, Notes App, Cable, Broadband apps, e-commerce apps, music apps everything has better presence and availability in the Android world.