Unfortunately I’m not sure on this, hopefully someone else in the know can answer that.
Although this potentially sounds like a task for a theme? Alternatively you could use independent components to make your own ‘form’ (there maybe more coding involved to collect/handle all the data this way), then you can use new-udbutton and specify your own text/label.
I would consider reading UD Load Testing
While this isnt about universal, just 2.9 version of UD, it’s probably still relevant.
If you’re looking at 1000 users as a userbase, you’ll need to ask what’s your expected average concurrent connections at any one time. If this is going to be a few, then no problem, but if you’re looking at 1000 users accessing the page all at once, you might have a few difficulties!