@Lalala75 I just wanted to chime in to say that I totally feel you on this and can commiserate. Also, as someone in a similar situation, where moving back to the US isn't the most feasible option at the moment, it doesn't seem very constructive or fair to suggest you that you should just say screw it and leave the UK, or go find some hobbies, as if those things hadn't registered already.
I am from LA too and have been living in England for almost 4 years now. There isn't a day that passes that I don't wonder if I could be living a better life (for me) back in California. I'd lived in other places, including Massachusetts and Scotland long before moving here with a view to stay indefinitely, so leaving the people and places I loved wasn't exactly foreign or even unwelcome. There are plenty of things I like about the UK and even prefer to the US, but I've also experienced and felt all the same things you mentioned in your post, down to becoming more patriotic than ever. I didn't think backlash contrarian patriotism could be a thing until I moved here! One of the most annoying things at this point, is that now that I've been here for a bit, and have had the privilege to go back to visit my family in LA a few times now, I don't really feel perfectly at home in either place. Moving back to the US is a possibility, but not in the near future. In the meantime, we have to try and stay sane, despite crappy avocados and no actual ambient warmth, ever.
Personally, I wish I lived in London, because while the smaller places are picturesque, my experience of living in them is that they are either provincial in mindset or isolated, both physically, culturally and socially. Maybe that's a "grass is greener" thing and London would be annoying too, but at least you have options of things to do there, eh? Have you lived outside of London before or do think you might be happier outside of a city?
There's a lot of systemic racism and sexism here - not that there isn't in the US, but it seems to manifest differently. Maybe it seems worse because one has already learned coping mechanisms/ how to navigate/think about US racism & sexism and then all of a sudden, one is exposed to new facets of the insidious -isms. Maybe I've had the misfortune of falling in with the wrong group of people here, but I've heard some nasty, vile, blatantly and unapologetically racist, classist and sexist things in the UK. Of course those things exist in the US and people say and do terrible things there too, but it is still jarring to hear it so openly here. I don't really know what else to say about that, aside from, it sucks.
As for food, KSand24 is right- spice things up at home! I lol'd about the salt thing though. I've taken to bringing covert deli packets of salt to in-laws homes where they've scoffed at my asking for a bit of salt. Also, this might not be very helpful, depending on whether or not you went to them back in the US, but I swear, going to Costco is like, my favourite thing to do when I'm homesick. Stereotypical American going to a big box store and weeping tears of joy at finding American-style marshmallows in a giant bag, shortly before the 4th of July? Priceless.
Sorry, this post has become long and meandering and I don't mean to have threadjacked to vent my own grievances. I just wanted to share some of my experiences too, to just say GURL I UNDERSTAND. Also, I'm totally going to check out that group on FB!