How to be a contractor - advice needed(engineering)

I’m really not sure where to post this, it’s tangential to finance but if there’s a more appropriate subreddit please let me know!

I’m a draftsperson working for a medium-sized consultancy. I’m going to move overseas, a move they know about and I’ve been planning for a while, and I’m trying to remove as many obstacles to staying employed as possible. One of those I’ve heard of from a few employers is tax - something about payroll being more complicated if I’m not tax resident. Can anyone shed light on this? Without fully knowing the situation I was thinking to sign up with a labour hire firm to get them to handle the business side and have me as a contractor to them (have done this before). I’m thinking this would make the deal more attractive to my employer if they can’t keep me on directly.

Any other advice is welcome!