yeah i was going to suggest the same... there are companies that do this, and honestly anyone with a little cash will lend you the money assuming the stock isn't a totally ridiculous thing.
How are the RSUs managed? Are they in a brokerage account? You may well be able to borrow from the broker.
The shares are not in our brokerage account yet. According to the company, they need to confirm the tax payment to the company before the shares are transferred to the personal brokerage account.
You don’t own shares. You own a right to future shares. Borrow against that. (If you want to roll your own loan, sell a deliverable forward. Again, not legal advice!)
How are the RSUs managed? Are they in a brokerage account? You may well be able to borrow from the broker.