Chatbots? That's not Google, that's the manufacturer or the carrier.
Text notifications? Use Feedback (in Settings) to complain about it. If enough people do, they may bring it back. Until then, use
SMS Popup.
As for the updates, most of them are security updates - and you wouldn't want someone taking over your phone via, say, Bluetooth, would you? (That was a security update a few years ago.) Some updates are o fix things like "could enable a remote attacker using a specially crafted file to execute arbitrary code within the context of an application that uses the library" or "could enable a remote attacker using a specially crafted file to execute arbitrary code within the context of an unprivileged process". Other "security patches" address security holes in drivers for hardware. You don't want things like that hanging in your phone, do you?
And maintaining an old version costs money. It costs Google, it costs the manufacturer and it costs the carrier - and that translated to more expensive phones and more expensive plans.
Some changes? I wonder about them myself, like taking the old list out of Maps. But time marches on and Android waits for no man. Some things we can complain about, some we just have to live with.