Live stream internet strength - Beach wedding

[haring]

One of my clients want me to provide live feed of the wedding ceremony they are going to have on the beach.
I would like to use my 5d mark iv to record and provide the feed into OBS Studio software. I am planning to use my mobile internet on my phone. I would like to set up my phone as hot spot and connect my notebook to my phone.

- My question is how to make sure I have strong internet to support the upstream data??? I don't have mobile wifi? The location is 2 hours away from my home. I can go and test the speed but I would rather not to.
What do you do when you live stream an event? How do you make sure you have a strong signal?