Does the verse (And that man shall have nothing but what he strives for) refer only to deeds in the afterlife and not apply to a person's striving in worldly matters, such as seeking provision, and does the context of the verses determine its meaning?

In the Hereafter, a person's striving is limited to their own deeds, though they may benefit from the striving of others if it is gifted to them. The context of the verses confirms that the Hereafter is what is intended. As for this world, a person has their own striving from what they have earned, and they may benefit from what others have bestowed upon them.

If the question is about seeing the fruit of one's striving in this world, the matter depends on the principle that whoever works and strives will attain the fruit of their labor. So, whoever seeks provision will find it, and whoever exerts effort in a task will realize its outcome. This applies to both believers and disbelievers, though the true blessing and benefit are for the believer.

Nevertheless, Allah may sometimes impede the cause, so it does not produce results, and a person may be deprived of provision due to their sins.