I am thinking of switching my phone from android to kalimobile and am wondering if anyone knows if it has a sim card based call app? Sorry if this is the wrong section but this made the most sense.
Why would you want to run Kali on your mobile? Kali is meant to be used as a set of security/pen-testing tools, Not to be used as a daily drive for your mobile or OS. Maybe if you have a secondary phone but not to replace Android, if you want to flash your phone with another Android version have a look at LineageOS.
What do you mean with "sim card based call app" if it's a real mobile OS it will have a phone app installed or are you talking about an e-sim app used for electronic/digital sim cards?