Instagram sets different live session time limit per your Instagram account type.

There are 3 Instagram account types:

As of January 2023, the maximum time limit for live session for Personal and Business account types is 1 hour, while for Creator account type the max is 4 hours.

To change you account type, check your Account Settings at your Instagram app.

Note: If your account is currently Personal, you'll need to select first "Switch to Business Account" and then you'll get the option to select Business vs. Creator.

See more info here:

https://help.instagram.com/1717693135113805