Last year we launched a public Magento 2.3 Commerce demo (which is now updated to 2.3.5). Because of the demand, we just launched also a Commerce demo with the official B2B add-on.
The demo is completely raw – default installation with sample data. And there are no restrictions at all – you can even break the website through the admin panel. All changes are reset every full hour so the demo is available for everyone without any restrictions.
magebit / Demo123
Hope this helps 🙂