https://www.amazon.com/Godox-Universal-Bowens-Speedring-Adapter/dp/B01JA4OOB2

I think that's what you want.

Just me, but if you don't already have the 300 SDI, maybe getting a SK300 II or MS300 which actually has a Bowens mount (and built-in radio triggering which gives you remote power/modeling light control) might make more sense.