We use dish detergent, put in a full bottle, fill and let it sit, then dump.
We have also put a bag of ice down the toilet before we head out and let it slosh around while we are on the road, dump when we get to our destination.
I’ve also done ice and dish detergent at the same time while traveling, same as above, dump when we get there.
Can’t say whether it helps or not but sure can’t hurt anything, so far no issues.