Can I combine SRAM Rival 22 Levers and Shimano 105 Rim Brakes?
For BR-5700, BR-5800, and BR-R7000 they run off the various new school Shimano not-quite-short-pull cable travel numbers. SRAM road levers are all basically traditional short pull, which is less cable pull than Shimano Super SLR et al.
The mismatch in this direction results in less pad movement but with more leverage than intended. It can typically be made to work, but needs to run with commensurately smaller pad gap, which usually means the caliper QRs won't open up enough for an on-trend tire. Feel will be mushy and indecisive but power will be good as long as you can get the pads close enough that you don't bottom the lever. By the same token, you have less ability to use the Doubletap reach screw.
It does function, but it always feels like a way of making a mediocre system out of good components. The pre-5700 brakes are normal short pull.