I've renegotiated (and given up) start dates for less. I'd "forget" and offer my phone as a substitute... expecting they'd get too comfortable calling or asking for work-adjacent things before preparations.

What's the rush, why not enjoy another week in the garden? Surely the paperwork and meet/greets can wait. On their part I'm seeing a lack of preparedness, adaptability, or boundaries; unsure which. Maybe a combination. Are you ready for this to consistently happen? They certainly seem more eager than anything else.

If/when they do get around to providing, I suspect it won't be long until your personal laptop collection grows with the end of another startup.