I've never had a velco preschooler, at least to that extent, but, oy, that would make me a crazy mama!
I think, if it were me, I'd start insisting on small separations. Itsy steps at a time. Like, she may wait outside the bathroom, with the door open, while you are in there. And then you can talk her through it, I'm safe, you're safe, I'm not going anywhere.
We have a rule that when mama is sitting in a certain chair that you need to be invited up. Cause dude.
I'm not a jungle gym.
I mean, obviously, that's a ways out for you.
Has it gotten worse lately? I've found on a few occasions when my preschooler is pulling in more, acting smaller that she's ready for new, bigger boundaries. That seems totally counter intuitive to me, but it's definitely held true.