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I think that case is very similar to yours. Have you tried the same setup with this small tweak:
STEP 1 - the same as described in that case. - it gets the call queue calls to ring only the deskphone.

STEP 2
create a custom rule for each user, just like in that case, but disable the poly phone in the Call Handling section. Pictured below is the only thing you need to tweak - click on the slider to disable the poly and leave only "My desktop and mobile apps" active.

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The alternative solution if the above doesn't work would be a similar in idea, but you would want to have an additional number assigned to the call queue. For example for a given user extension you would have 2 numbers to reach it on. Number1 - the direct number and Number2 - the call queue number.
You can then create a custom rule with conditions -> if called on number1 ring the app.
if called on number2(i.e on the call queue) -> ring the poly.
The reason I mention this secondly is because it involves getting an additional number which costs something like 1 Euro?