For example to Australia or Canada specifically, what would you recommend an 18 year old studies at university, or a specific career path to achieve this. This is without taking into account specific interests, where the only purpose is to gain skills to emigrate?
Engineering, software development, a good trade like electrician.
I would say to first have a goal of learning proper English grammar. “whose”, not “who’s”.
Medicine.
Tech will be saturated for awhile.
Or any of the trades.
Pick a subject you both like and are fantastic at (world level great) then check university links from the UK institution to the country you want to live in.
Get onto the exchange programme. Study there. Look for post-grad options in that country leading to either local job at senior level intake, or PhD and post-doc work there.
Why would that be your only goal?
Plumbers in Norway live like kings
Big Finance / Big Law / Big Tech are all good
Australia and Canada are not big in any of those areas
Any type of engineering
I second this
Construction/engineering has been good to me and allowed me to work all over the globe with family in tow.
Québec will love you if you learn French first.
Same for western Switzerland, and good old France.