Few things to remember here:

1. Function timeout -1 does not mean infinite. Maximum timeout here is 5 minutes by default (00:05:00).
2. If you feel your function might take more time in execution, divide them in multiple activities and try to use Durable Functions which will help you to work with multiple activities till your execution is complete. Here, also remember that each activity will also be having maximum timeout of 5 minutes including orchestrator functions.