yes i have, my webapp UI was built on lovable. The UI features/aesthetic has worsened lately (I built mine on an earlier version) - I hope they fix it!
I have used Replit also - a decent tool.
For both, ultimately to make something work and take it to market you need an engineer/team. I took my lovable UI to an engineer team in India i have and having them build it out (cannot be done by me a non technical person alone).