Hume's Guillotine sets up an ethical regress problem

[MindForgedManacle]

Not sure what you mean. Hume's is-ought distinction merely points out that you cannot go directly from a descriptive statement to an evaluative statement... without some means of showing why they follow. That is, one must argue for it. It was never meant to be seen as insurmountable. In fact, Hume saw it's real use as a good way to beat down any religious moral system.

So, I could cross the is-ought gap fairly straightforwardly via goal-directedness. For example:

If I want to win a race, then I ought to run the fastest.