You might want to bring a 100 $ old Lenovo such as x200 (ideally with Libreboot, to justify youself)

Or you may go further and bring a 30 $ used/old laptop with 1G ram and a stipped-down Linux such as Alpine+fluxbox. Your employer should quickly understand that they need to give you a new machine for you to be productive :)

Or even further, you may also say that you only have a fixed desktop computer and no laptop.