There is no recommendation to eat 10 different fruit & veg per day. Two years ago there was an Imperial College study that identified that health benefits peaked from consumption of 800g per day. As a serve is defined as 80g in many countries, a number of news outlets (cough, Daily Mail) sensationalised it as 10 different fruit & veg per day.
There is general advice around to aim for 20 different types of fruit, veg, grains and nuts per week, to help with gut biome diversity, but this doesn’t mean 20 per day.
I do manage 800g on around 4-5 days a week but I have a strong motivation - endometriosis and managing inflammation - which it massively helps for me. I think it’s a tricky thing to do if you don’t have a strong driver. I was a huge salad dodger as a child but now chow down a big salad most days which is where most of my consumption comes from.
An 80g serve actually isn’t that much. It’s half a red pepper, half a pear, 7 cherry tomatoes, 4-5 big mushrooms, 3/4 of a banana, 2/3 of an apple, 4-5 strawberries, 1/3 can of chickpeas, 4cm of cucumber... it’s only raw leafy veg that is a massive volume at 80g. To the PP who ask how a single omelette can hold 4 veg - it’s definitely quite possible if you cook down the spinach, mushroom, tomato and peppers.