The workbench is an unsupported product. You cannot escalate the issue. We don't know when, or if, this bug will be fixed. You're welcome to try and diagnose the issue yourself (it is open source) and submit a PR (I've done this before, it's not too hard), but there's no guarantee when it will be fixed.
You can spin up your own copy on a private Heroku stack, which is also not difficult (I spun up one on Heroku). I've considered hosting my own copy, but unless I receive donations, I can't guarantee that I can keep my own instance running, scaling up Heroku is prohibitively expensive for someone with my income. You're free to try and use my copy for now, but I make no guarantees of availability.
If this continues indefinitely, I am considering building a brand-new Lightning-based app to fill this gap. If there's significant interest in such a product, I would consider doing so.