If your employer wants you to use some specific technical tools, they need to provide those tools. Be respectful, but firm.
I would recommend simply leaving your laptop at home.
also, this 'startup' is not in good shape if they can't provide you with the tools you need to do your work. it sounds like a sinking ship, and you should simultaneously be preparing your exit strategy asap.
If your employer wants you to use some specific technical tools, they need to provide those tools. Be respectful, but firm.
I would recommend simply leaving your laptop at home.