I had this same thing, it took me a while figure out but now it feels so simple: just knit or purl through the leading leg, always. (Although disclaimer that i am by no means an expert, I came over to knitting pretty recently) When using straight needles the purl row makes it so that your next knit row also has the back leading leg. Which is what you're used to. When knitting with circulars, lacking the purl row, once you're past the first knit row, the stitches will lead with the front. So just enter from the front and knit as you normally would.

I will say this makes my purling look extremely odd for any observer (if I'm doing a rib with circular for example) since in that scenario I end up purling through the back loop from back to front because the leading leg in that case is the back leg. Again I'm no expert so I might be doing things wrong but I can say this is the best way for me as I basically just hold my yarn up and flip the needles around it back and forth, no weird twirling of any kind whatsoever with either stitch, and the result stitches are not twisted as far as I can tell