"Make this supply-limited good available" is a problem that markets love to solve; in fact we do quite a lot of work to place constraints on many markets so that their solutions take forms with specific properties. In principle, we can relax constraints. USA baby formula at the time had very strong constraints ("nutritional labelling must take this precise form", https://www.accessdata.fda.gov/cms_ia/importalert_116.html) which could be relaxed.

Very easily. There's no baby formula shortage in the UK or EU, so why not pass emergency legislation that allows them to provide the US market and pay the EU/UK producers up front to ramp up their production until the issue is resolved.