It depends really on what you eat now but things I did (attempting to eat 80% non UPF):
Bread maker , so quick and easy to use and you can make brioche, raisin bread etc to replace some cakes/biscuits. Also make homemade pizza dough in it (also much cheaper and nicer). I do use yeast that has an emulsifier in but figure it’s such a tiny amount I’m ok with it.
Swap biscuits to shortbread (look at the ingredients but some are non UPF)
Home made hobnobs - mix equal amounts of sugar, SR flour, melted butter and oats. Make small balls, flatten slightly and put in the oven on a baking sheet for 15 mins at 180 degrees. Let them cool slightly before transferring to a wire rack (they’re quite soft when they come out of the oven but do firm up). You can also add raisins or choc chips before cooking or drizzle with dark choc after (there are some that are non UPF but I tend not to worry for a small drizzle!).
Swap crisps to Aldi posh lightly salted crisps - just potatoes, oil and salt (sone people say rapeseed oil is bad but I’m ok with this). Dip in apple cider vinegar while eating for salt and vinegar.
Passata or Aldi tinned cherry tomatoes have no preservatives etc in whereas many tinned tomatoes do.
plain Greek yoghurt with honey/maple syrup and frozen blueberries or chopped toasted hazelnuts and a spoon of cocoa.
soda stream or soda water with posh squash (I like the bottle green ones, the elderflower is lovely) or mixed with fresh apple juice rather than fizzy drinks.
roast a chicken Or tuna, cheese etc for sandwiches rather than ham/salami.
Aldi all butter croissants are non UPF.