A little effort does go a long way. Using mason jars, I regularly buy veg like capsicum, mushrooms, celery, leeks, etc, and chop them up to use here and there in various dishes, like rice and pork. I precook the mushrooms, obviously, considering they're pretty hard to overcook and won't go moldy on you. One advantage to this is that you can save money on pizza by grabbing a few frozen ones at the store and customize to your heart's desire.

I tried a similar thing as you have years back. I enjoyed eating Jimmy John's Sorry Charlie/Club Tuna sandwich so much that I started to replicate it at home. It wasn't exactly the same but given what I know now about fast food bread, I'm pretty sure it was a touch healthier. One trick I've taken on in that regard is to not use mayo when required, but substitute plain yoghurt instead.