No tofu is generally not processed and is often fortified with calcium etc
Well it doesn't occur in nature in that form so it must be processed to a degree. Likewise yogurt, all the vegan milks etc.
It's a spectrum and all about balance. Lots of common vegan foods, eg avocadoes, quinoa are grown intensively on the other side of the world, probably on mega farms that hoover up massive amounts of water. All the processed burgers etc will be made on production lines in massive factories. Then there's the health issue, a lot of vegan foods contain a long list of ingredients so definitely fall into the UPF category.
The list posted by @TheSlayer is probably a good place to start if you're not vegan for animal welfare reasons. And any reduction is a good thing.
So if you go from eating red meat most days to only eating very occasionally, eating a bit of chicken, but having lots of plant based/low meat meals, you've reduced your carbon footprint. It doesn't have to be all or nothing. Maybe think of a few vegan/vegetarian/low meat* meals and mostly cook those.
For burger type foods at home, you could probably try making your own bean burgers rather than buying in ready made ones, especially those that attempt to replicate meat so will have extra ingredients and have been 'texturised'.
*Low meat. Instead of serving steak and chips, make fajitas and only include a small amount of steak and lots of peppers, onions and beans. Likewise chilli can be a small amount of meat (try turkey instead of beef to reduce carbon footprint) and lots of beans and veg. A pilaf with a small amount of chicken (eg one thigh per person) plus chick peas, spinach, onions. Stews or soups with lots of pulses and veg as well as a small amount of meat per person.
Then if you've been here for very long, you'll be familiar with the concept of the much maligned Mumsnet chicken, but that's actually a long standing way of eating meat from a time when chicken especially was very expensive, had to do a few days meals with everything used and was only part of the meal, not the main focus.
Which illustrates the problem, 'normal' is now relatively large portions of meat, eaten most or all days, sometimes more than once. So if you go down to eating it only a couple of times a week, and smaller portions, you've cut down the amount of meat you eat and the impact of that by probably 60-90% depending on how far you go and where you started from. If most people did that, the benefit to the environment would be massive.