Welding masks have replacement
glass filters. These used to cost <$3 to replace. I recall using them to observe solar eclipses with no (or minimal) damage to my eye. But this will ruin the color of the sun. (normally turning it green). But you could use it between you and the camera if not between the camera and the sun.
I wonder how homogeneous the surface (photosphere) is, if by using several hardcore filters of different color (freq) could you reassemble the sun surface images with some 'narrow band filter techniques' like you always see on Hubble telescope images. Would you see much texture/sunspots/