It is a truth universally acknowledged that gluten-free bread is about as appetising as cardboard, as well as being ridiculously expensive - often up to three times the price of normal bread. When you consider the impressive list of additives - hydroxypropyl methyl cellulose, vegetable glycerol, xanthan gum (as well as brown sugar and caramel to turn it brown) - it makes you wonder how supermarkets can get away with displaying it in the ‘free from’ section. That said, it’s far better now than it ever used to be. As Jennyjoan has said, Genius is one of the better ones. My wife (who is not coeliac, but is intolerant to wheat) also rates M&S and Waitrose.
Deliciously Ella does a decent range of GF muesli and granola.
Most pubs and restaurants have some GF options these days, and even if they don’t, they are often happy to do a jacket potato or an omelette. It’s worth letting them know when you book. If you like curry, most things on the menu in an Indian restaurant are GF (apart from the bread of course).
As Maydup says, GF pasta is good - I can’t tell the difference!
My wife has had no difficulty finding GF food in France, Spain, Malta and Portugal - and we now know how to say “gluten-free” in half-a-dozen languages! Airports can be a bit of a problem, though, so she always carries a couple of GF snacks with her.
There is a useful (and free) app called “Find me GF” to help locate pubs and restaurants that are GF-friendly.
I can understand you feeling down about this, but it’s not as bad as you think - and it’s getting better all the time.