I have used the 3 sisters method of planting with success, but you do need to plant drying beans and make sure the sweet corn is where you can reach it, so you are not having to wade through the squash foliage on a regular basis to get to either.
This year I have a new idea that I have seen someone else do. New Zealand spinach which you soak the seeds of overnight, then sow direct between your sweet corn plants as ground cover and to eat. I have the seeds ready to go, so we will see how it goes
Another one I have used is to sow a climbing bean seed or two at the base of sweet corn plants once they get to a decent size. The beans climb up and you leave the sweet corn stalk standing as a support even after you have picked the corn itself. You can get a pretty decent crop of beans without affecting the corn.
I would say as a proviso that for all the above, the sweet corn on my plot would be growing either on a ‘bean’ trench that I would have prepared over the winter or on soil which as had a good layer of home made compost added to it as a mulch. No point trying to interplant on hungry soil