This simple patch adds a custom block without GPS by turning Map16 tile 131 into a solid slope assist tile i.e. a block which is solid from the bottom and sides but acts like a slope assist tile from above, allowing you to connect slopes with a wall at the base and have an almost solid 1F0.
Do note that you can still clip through the normal and gradual slopes with slope assist tile with correct angle, which to be fair is also the issue with the original slope. Normal players are unlikely to clip very often through these as the clips are pretty precise. The slopes are pretty janky in general so there's only so much you can do.
Otherwise, there aren't any issues I found with it, works with all slopes, including very steep slopes, conveyors and even pink triangles, on layer 1 and layer 2. Can be a viable alternative to the GPS version (if you don't want to use that for some reason).
There seems to be a major issue with how this affects the slope tile itself, above the new assist tile:
(In this gif I wasn't connecting the slope with the wall at the base like in your example gif; but I had the same issue when I tried that, too. Also, I'm definitely using the new tile 131 as the assist tile, and this was tested on an otherwise completely clean rom.)