You would perhaps need to change the viewpoint for that. Theoretically, there is nothing which can't be achieved - functionally - without FPGA. However, that doesn't mean some problems can' be solved more conveniently using FPGA, and the solutions turn out better in some regards.
But I too was (edit: also still am!) interesed in fpga so I was just scrolling and I found this really really great video (I can't recommend this enough, so much so that before reading your comment that I actually submitted that video as HN submission)
Also check out what this guy has been doing with old factory robot machines and using FPGA for them was a really practical use of it and they have another video about it too that you can find on their channel.
Some parts of the video especially near the end went really really out of my head but this might be one of the best videos about FPGA judging from the comments and I just really loved it man, so that's about it yeah, I recommend watching the video!
i was thinking of using FPGA to control led matrix, the algorithm is not hard, it's just there are too many pin to control, they need high clock rate if you want high color depth, a using MCU bit bang is not really a choice.
And Colorlight i5/9 boards are made for that very application; it just so happens they're a reasonable minimal devboards for ECP5 FPGAs. I don't think right now you can get anything more capable for the price (Yeah, there are super cheap decommissioned miners with Zynq, but there's almost no I/O fanned out.)