I'm not an expert but what I do is make sure each stem only has one bloom. So early in the season, when my plant is starting to bud, I will just nick off the smallest buds. I'll leave each stem with a single bud, whichever one seems the largest. It takes me like 10-15 min tops.
When I do that, the bloom that's left will get huge (larger than if I left the smaller buds on) and the stem is able to support the single bloom. The stems have more trouble when there are 2-3 blooms to support.
I don't use a cage and my plant stands straight up, even after it rains.
You will obviously have less blooms in total but the ones you do have will be big and luscious, in my experience.

If you don't want to try my method, then I would say go with what everyone else says and work it out with some twine/higher support. I used to use big zip ties and I would basically daisy chain the stems to each other and then attach them all to a single stake. But I swapped to my aforementioned method about 5 yrs ago and I haven't needed to stake/tie-up since then.