I’m coeliac and genuinely once you’re used to it, it’s fine. I find the issue isn’t the availability of food, it’s just always worrying slightly when you try somewhere new to eat out, always double checking packaging.
For good bread from a supermarket, the Warburtons tiger bread is the best imo. Waitrose also does a good sourdough. Tbh they’re all mostly ok toasted but some cheaper ones are a bit dire. The best gf bread I’ve ever had is the brown loaf from good grain - you can search them up and buy it online.
Pasta I can’t really tell the difference anymore tbh, pizza express does a good gf pizza and the Schar bases are decent too. For a cheeky frozen pizza. White Rabbit is nice for a fancy ish one and Goodfellas do a basic one.
I also eat things that say “may contain” and have always been fine by YMMV. It just means things like cadburys, walkers etc are ok.
in terms of home cooking it’s very easy to make things gf. Consider a separate toaster also, or you can get toaster bags. Coeliac U.K. have them - incidentally, my mum (who has been diagnosed my whole life) joined for us when I was diagnosed but I’ve honestly never used their stuff. That might be because I’ve grown up familiar with it though.
Travelling is largely fine - you can easily Google it ask ChatGPT for GF recommendations but honestly when we go away, especially in Europe and ESPECIALLY in Italy, we often bump into little gf places that we didn’t see online.
The one issue I have with availability is the lack of lunches you can get “on the go” in supermarkets. You have to go for more “picky bits” (M&S do a nice 3 for £8 selection) or sushi (the Tesco one has gf soy sauce!). Never be drawn in by a gf pre packaged sandwich. Awful.
I actually lost a lot of weight when I found out I was coeliac because I lost a lot of joy in eating but honestly it’s fine and I eat well and normally. You just have to get used to it!