It's apparently pretty hard to hit the Sun:

https://www.youtube.com/watch?v=LHvR1fRTW8g

(Though that video mostly talks about small objects like rockets. Maybe it's a different story for dwarf planets?)

That said... Keep in mind that this is about a dwarf planet orbiting the Sun. It's 11 AU out, so twice as far from the Sun as Jupiter is.

More importantly the video mostly talks about hitting the Sun from a platform like Earth already closely orbiting the Sun, which is not the same thing as arriving practically from interstellar space. That's much more important than the size of anything.

If you were to make a velocity change to this object in its aphelion to make it hit the Sun, it would be vastly easier (at least per unit of weight) than do the same with a probe launched from Earth.

A direct hit with the sun? Maybe slightly higher temperatures if the "impact site" was facing us, but not for long because the sun is highly convective and each "longitudinal ring" on the sun rotates differentially, thus dissipating the effects of that impact very very quickly. A good chunk of it would also probably burn up before even reaching the Sun, but how much of it is hard to say.

But keep in mind, it says "within 11 AU of the Sun", which is still beyond Saturn; Saturn's 9.5 AU away from the Sun, and Uranus is about 19 AU away from the Sun. So it's still pretty far away.