Two options that I am aware of, dam strip (mounts on floor) or a sweep.

Here is a similar issue and how they kinda resolved it. [https://www.houzz.com/discussions/water-spilling-out-from-new-frameless-shower-dsvw-vd~2862377[(https://www.houzz.com/discussions/water-spilling-out-from-new-frameless-shower-dsvw-vd~2862377).

i think I would really look into your floor slope though. I believe a properly built curbless shower should not even need a glass door to keep the surrounding floors puddle free. That is a large puddle. I say this as one who is having my three month old poorly sloped shower ripped to studs and redone so I get not wanting to fix the real issue but it is worth a few more weeks of hassle to get a properly waterproofed shower that lasts for years.

Millworkman, your suggestions and turning water pressure down were the solutions that helped in the thread above so you are right on the money with a great bandaid solution ;) but as a woman who believes water pressure to be my best friend I would go the extra mile to have my shower fully function;)

As would I.

Thanks for the replies, and I'll take a look at that other thread. I'd definitely prefer to not have the floor redone; while it's not out of the question, I'd like to start with trying the least-painful solutions before working up to big ones.

I expected there might be a little overspray/splashing, and drips when we open the door out, and that's fine. This, however, is beyond that--it looks like a portion of the water that sheets down the door hits the floor and then exits the shower enclosure, maybe because surface tension pulls the water out a bit to where the floor isn't sloped. Does the slope on curbless showers ever start outside the glass, like at the seam closest to where my finger is pointing in the photo?