Actually, it seems that google is now able to cope with things a bit better. I've just tried and I can now ask for "how long left on my 45-minute timer?" and it does finally answer. It actually also shows up in the UI. That is sort of recent, though, as I've had that problem earlier this year. It seems that siri is now unable to set multiple timers, though.
Anyway, it does seem to have improved, but I wonder why that stuff wasn't in from day one. It seems pretty obvious to me.
Weirdly, the ability to set multiple timers varies by the device you are using.
A HomePod can set multiple timers. A Watch, iPhone, or iPad can only set one timer. There is no obvious technical reason for it. It just seems like only the HomePod team thought it was an important feature.
This becomes annoying if you have multiple devices set to respond to “hey Siri” and the wrong one picks up the request and then refuses to comply.
Oddly enough, in the iPadOS 15.7.1 at least if I say "Hey siri, set a timer for 20 minutes" it will say "20 minutes, starting now". Then if I say "Hey siri, set a timer for 5 minutes" it says "there's already a 20 minute timer. Replace it?"
If I say "set a timer for 20 minutes called A" it just ignores the "called A" part.
I do "Hey Siri set a timer for Foo for 5 minutes" I get a timer named Foo, and I can then set concurrent timers named Bar, Baz, etc. without replacement.
Anyway, it does seem to have improved, but I wonder why that stuff wasn't in from day one. It seems pretty obvious to me.