While you can read any of his books out of sequence, I strongly recommend following one of the paths here: https://upload.wikimedia.org/wikipedia/commons/1/12/Discworl...
While none of the novels are impossible to read without having read the previous ones, many of them build on the themes and the characters that came before, and some of the magic is lost without knowing what came before.
Following that guide for first reading is probably the biggest mistake I have made in my 42 years of being alive.
First time you read it should be in publishing order.
I think it's OK to skip the first two.
Those two Rincewind novels were when the Discworld books were parodies of the fantasy genre curca ~1980. If you aren't aware of the tropes of that genre the jokes don't hit as well.
From Equal Rites onwards Terry realized that the Discworld was much more interesting as a lens to reflect on human society. That idea kept him going for the rest of the series.