Gather POST request on HTTPS traffic?

Hello everyone

I work at a digital agency that has quite a few machines that are managing some Instagram accounts, we are using Squid as a proxy to log and analyze some usage statistics and to make sure the machines are only used for Instagram.

We had an idea to use Squid to capture the POST data of users on the proxy level, for example, likes, follows, comments, etc so we can log and analyze everything in a convenient central way, so we can analyze it and even send out clients a monthly report of all the actions their accounts made (who they followed, what they liked, etc).

I can easily see the requests that I want to capture inside the "network" tab in Chrome but the problem is that Instagram uses HTTPS, so I can't seem to be able to capture this data.

Is there any proxy software that can capture this kind of information from any clients connecting to it, without the client needing to set up anything but the proxy itself?

I have seen some solutions like fiddler but they require you to set stuff on the client machine other than the proxy and I don't want to waste time going over every machine.

Note: We are aware of the legal issues, all machines connected to the network are company property, and all the accounts are client accounts that allow us to gather statistics. No personal account data will be gathered.

Thanks.