This might help you get started perhaps:

https://community.home-assistant.io/t/twitter-follower-count-sensor-no-api-integration-required/161858

I know it’s Twitter so it’s not entirely relevant.

And then there’s also this:

https://community.home-assistant.io/t/mastodon-follower-count-and-other-profile-sensors/561095

Apologies if it’s not exactly what you’re looking for but IMO, Home Assistant might be the easiest way to get this kind of API interaction with actual motors and microcontrollers.

• create an access token (reddit thread)
• I found this post from last year linking to API Docs
• official GitHub repo link

This is not just one simple question.

You need to break it down into smaller tasks.

First things first, you need to get data from a Pixelfed instance, ok, start by looking up how to connect to the Pixelfed API.

Once you have a way to connect to the API, you need to request the data you need.

Once you have the data, look at the actual data, do you need to do extra formating?

Once you have the data, it is time to get/build the display.

Once you have the display, you need to figure out how to get your computer to talk to it, is it as simple as just sending the number to the serial port or do you need to use something like the GPIO interface on a Raspberry pi?