Private driver from Stresa to Zurich

Stresa to Zurich is about a 3.5 hour drive- cost will be very high- probably close to 1000 Euros.

I think flying is your best choice.
There is a direct bus from MXP to Stresa and vice versa.
Alibus
https://www.safduemila.com/linee/alibus-malpensa-lago-maggiore/

A driver from MXP to Stresa is about 180 euros- we looked into it last year.

We did use this company for other transfers in the area:
https://connectotransfers.com

If you are flying in to Milan on 9/19 or 9/20 then going to Stresa and need to be in Zurich by 9/21-you aren't giving yourself much time.
That's basically 1 jet lagged day in Stresa.

Easiest from Stresa to Zurich is the train. Takes between 4 and 5 hours. Going back to MXP and flying will take longer, and will cost more. Alternatively you could make this a scenic trip. Take a boat from Stresa to Locarno, and a train from there.

You might look into the SBB luggage transport option. https://www.sbb.ch/en/station-services/before-your-journey/luggage/luggage.html

You would need to get your bags to somewhere in Switzerland. Then they could be delivered two days later to your destination in Switzerland. Sounds like a bit of a logistical challenge though. How are you going to manage your luggage on your tour?

Check Bellagio Taxi for a private driver. We have used them twice. Once for Stresa to Locarno so maybe they'll do Stresa to Zurich or can recommend someone. For 4 of us from Stresa to Locarno one way was $300 Euro

Frankly, I would take a train Stresa-Gallarate and then taxi to Malpensa - but maybe a shuttle Stresa-Malpensa could be easier. Then, fly to Zurich.