I have some suggestions that may help. Take a look at the map of the Swiss railway system, and the attached schematic of the scenic routes.
https://cdn-doc.myswissalps.com/docs/default-source/rail-network-maps/swisstravelpass.pdf?sfvrsn=7788603a_56
First, with an 11 am arrival at Zurich, you can easily head straight to Zermatt from the airport. The journey is only 3.5 hours, and there are trains departing the airport each hour at 45 minutes past (11;45, 12;45, etc) with only a single change at Visp. In between, there are several other trains with an additional change, usually at Bern. You could arrive in Zermatt, where you want to be, by mid-afternoon, with time left to get outside and shake off the travel fatigue.
Now for the scenic journeys: the Glacier Express is a long time in a train, but you can break it into two smaller sections that include much of the best scenery, and still and allow you to reach the places you want, as well as take the Gotthard Panorama Express and visit Kandersteg on the way. Like this:
After 2-3 nights in Zermatt, you head to Wengen via Brig and Kandersteg. This will put you on the Glacier Express route between Zermatt and Brig, but you can ride a regular train instead of the named Glacier Express if you like——it is a short ride, and the scenery is the same. From Brig, you head to Kandersteg, avoiding the deep Basistunnel that bypasses Kandersteg. You will still have a tunnel, but it is much shorter. You can see the tunnels on the map, indicated by dashed lines. Stop for a few hours in Kandersteg, or spend the night—-maybe at the mountain inn up at Oeschinensee. (We have done this several times)
Www.Oeschinensee.ch
There are lockers in the Kandersteg train station where you can store your luggage while you explore, or overnight if you want to spend the night at the lake. Or you can take your bags up on the gondola to the lake (we have done it both ways).
From Kandersteg you take the train to Wengen, connecting at Spiez, Interlaken, and Lauterbrunnen. Spend 2-3 nights.
Then head from there to the Grandhotel Giessbach on Brienzersee. I believe you reach the hotel by boat from Brienz—-always wanted to go here but we haven’t made time for that so far.
After a night at the Grandhotel, continue from Brienz to Luzern—-this will be the scenic Golden Pass route, but you will be on a regular regional train. After 2 nights at Luzern, you take the Gotthard Panorama Express boat and train south, but only as far as Göschenen. Get off there and take the 10-minute train ride to Andermatt, where you can pick up the Glacier Express heading east to Chur. This would put you on the late Glacier Express train which departs Andermatt at 15:54. Alternatively, you could stay on the Panorama Express to Bellinzona or Lugano, overnight there, and the following day take a regional train back to Andermatt to catch an earlier Glacier Express—-in summer they pass through Andermatt at 10:54, 11:54, and 12:54 as well as the 15:54. Either way, you end at Chur and depart to Paris from there.
You could also do the circuit in reverse, by riding a different section of the Glacier Express. From Zermatt, take the regular Glacier Express all the way to Andermatt, and transfer from there to Göschenen for the Gotthard Panorama Express to Luzern. (You will have to check the schedules for both scenic routes to make sure this will work—-you may have to overnight somewhere as the northbound Gotthard PE stops in Göschenen at 11 am). After your time in Luzern, you ride the Golden Pass route to Brienz for the Grandhotel Giessbach, then continue to Wengen for your final stop in Switzerland, departing for Paris from there.
This latter route gives you most of what is reputed to be the most scenic section of the Glacier Express, between Brig and Disentis, although you would miss the last part unless you stay on til Disentis, disembark there, and backtrack to Andermatt. TBC