How many users can connect to my hotspot?

Keep in mind that you will be charged data usage for each device connected. That can add up quickly.

There is no documented limitation from Apple, all they mention is it depends on iPhone model and carrier.

How to set up a Personal Hotspot on your iPhone or iPad - Apple Support

The number of devices that can join your Personal Hotspot at one time depends on your carrier and iPhone model

Most sources online mention a 5 to 10 device limit with some carriers possibly limiting it to 3.

https://apple.stackexchange.com/questions/82276/does-ios-cellular-tethering-limit-the-number-of-wifi-clients

All you can do is test it and see how many you can connect.