In that case, try boiling a mixture of baking soda and water in it, then scouring it using tongs with copper wool (I’d probably use steel wool, but that might also leave scratches, I don’t know). If it’s giving your food a taste, it is coming off, just really gradually and under high heat.

There’s probably a local equivalent; looks like the primary “ingredient” is Oxalic Acid so a cleaner containing that would probably work just as well

So the legend of bar keepers friend is that it was invented after someone boiled a bunch of rhubarb greens and noticed it cleaned the pan. I reckon any green high in oxalic acid (the main ingredient in BKF) should do similarly enough to the actual product to let you know if it might work.

Perhaps you’re cooking them too hot? Or perhaps you’re getting uneven heat (e.g. an electric coil stove)?

Corn tortillas really shouldn’t be at risk of burning like that.