What URL can I hit to initiate call?

I'd like to be able to hit a URL with CURL from my laptop, and have it cause my android phone to initiate a phone call, on speakerphone if possible. I'm using a Linux laptop with Firefox browser, and I have tel: links set to run a bash script. I'd like my script to send a GET/POST to some google cloud API which subsequently sends a command from the cloud to my phone that causes my phone to initiate a phone call hands-free to a number I send in the GET/POST. I will use this to make tel links clickable in my laptop's browser. Browsing on android sucks. Calling from a "hangouts tab" in the laptop sucks. Combining in this way will avoid the most things that suck, which is my new years resolution. I may also use this to automate calls to appointments/meetings that I need to attend. i.e. at the correct time, my phone simply auto-joins whatever zoom meeting, without me having to remember it. Bonus points if this API can also, optionally begin the call on mute.