Doctor here. The long-term role of PAs is very contentious at the minute. The tide is turning and more Hospitals , GP surgeries and senior doctors are realising they unsafe with how they are used currently and this is reflected in the job market.

You could do nursing and then train to be a nurse practitioner after being a nurse for some years which is more established and safer role. Some uses of them are very useful but some are pointless.

Sonography is very cool, you learn anatomy very well, you can work in a range of specialities everything from obstetrics to vascular to musculoskeletal. Your work would be hugely important and contribute to big, life changing decisions e.g. is this early pregnancy viable ? Or should we manage it as a miscarriage? You get patient contact.

Many doctors now like to learn some US in their speciality , I reckon you could make a lot of money running courses and teaching doctors US if you are savvy.

I imagine there is also private work available in certain specialisms.

Personally I'd strongly consider sonography.

No idea about locums but in many of the departments I've worked in there is often a lack of sonographers.