I love these barn-door tracker builds. I did one myself and did some fun high school math along the way to do tangent corrections in software. Fun times. [1]

[1] https://partofthething.com/thoughts/making-a-cheap-and-simpl...

I am not an astrophotography guy, and I have not built a barndoor tracker (yet), so take this with a grain of salt, but I'll skip right to the double-arm type here if ever get around to it:

https://www.pentaxforums.com/articles/photo-articles/astroph...

Maybe with a Raspberry Pi camera.