Which is better: remaining in Saudi Arabia or returning to one's home country, taking into consideration the saying that one's destined provision will reach them wherever they are?

Sustenance is predetermined for its owner, and a person will not attain anything except what has been written for them, whether they strive for it or not, and whether they remain in their homeland or travel. This is based on the حديث (Hadith): "Indeed, the Holy Spirit breathed into my soul that no soul will die until it completes its term and receives its full sustenance. So, fear Allah and be moderate in seeking." A Muslim is obligated to strive and earn a living, and this does not contradict reliance on Allah. Striving to seek sustenance and residing in another country for work is permissible and acceptable شرعاً (religiously). What you obtain from this striving is what has been written for you, and it is not correct to say that you are taking someone else's sustenance.