There seems to be lots of cost and regulations depending on location.
This is the best article I could find.
https://coinatmradar.com/blog/revenue-and-costs-of-running-a-bitcoin-atm/
In the US we would need to register as a Money Service Business with FinCen and adhere to different state laws.

https://www.acfcs.org/news/330368/A-Beginners-Guide-to-Operating-Your-Own-Bitcoin-ATM-and-complying-on-AML.htm
We would need to set up Anti-Money Laundering compliance program.

We would need to start with the legal basis first, and determine where we plan to set up the ATMs to know which laws we need to adhere to.