Chick fil A is not your typical franchise. You're not buying into anything. You'll put up a very small fee and if selected ( remember the religion aspect) you will have a very good restaurant job but you'll have to operate the restaurant. Its not passive but very hands on. Its not like you're buying into a Subway, Jimmy Johns, Wendy's, Papa John's. Etc. If you're wanting in that game look into WingStop. You want a VERY strong digital, Takeout and delivery system.
Also you're not going to be able to just buy a successful franchise unit like a WingStop or McDonald's unless you can open a new market so forget any of the large brands. Now can you buy a couple Subways off someone sure but have fun. Most of the large successful franchise brands are operated by large companies/PE with big money. Groups that operate 50 WingStops or 100 Wendys all in established markets like a D/FW or Houston.