There might be a way to make it work still. Most of the issues I pointed out above could maybe be worked out with some clever editing.

For example, Kylo kills Han, but Rey and Finn just… escape successfully.

Then she reaches Ahch-To and trains with Luke, and has Force-Time sessions as well.

Then the duel happens later as you pointed out, just cut Finn and the whole lightsaber pull thing. Don’t know if that’s possible.

Problem though is that with this, they would be going to a similar-looking location twice. 😛