I haven’t been to Zermatt in Summer, and it’s been 15 years since I went in winter.
To be honest it was expensive back then when there were two Swiss Francs to the pound.
However it’s an amazing place and well worth visiting IMO.
In the absence of more up to date advice I’d suggest avoiding eating in any of the mountain restaurants, apparently a pizza can be £40-50, and instead get food in one of the supermarkets in town.
If it were me, I’d look at getting the Gornegrat train up with my bike, because the train is the archetypal Zermatt experience and then look at one of the routes down from there. I think there is an e-bike route from Tasch, but it would be a shame to miss out on the full Zermatt experience IMO.
The Gornegratbahn is expensive, but I believe that there are ways of making it cheaper with reductions on the walk up price?