I use the 300 PF with TC for insects, it gives me very close focusing distance. It's very sharp, but not as sharp as the 500 PF. It also focuses a bit slower.
That’s a lot of clicks, but also not a big deal. Your D3300 shutter should have another 100,000 or more clicks left in it 😊. I have a D500 with 400,000 shutter actuations, and it still works great, although I did have to replace the shutter once.