Good alternatives for peri peri include jalapenos, habanero and cayenne peppers. Or you could try ready made mixes of chili powder and paprika. You want to recreate the heat of piri piri without becoming overpowering and a mix of alternative peppers can be the right idea.
There is more than one type of paprika, using hot chilis or sweet plus you can make it smoky as well. Chili powder will vary but uses chili’s, cumin and garlic powder. Again you can find variation in terms of heat developed. Cayenne pepper is a hot and fiery pepper used in some of these mixes.