For writing/reading? A pen and a notebook: weeks/months autonomy, lightweight, works also when under the rain or in cold and almost unbreakable. Ditto for a paperback book or two.
For photo? A Mac (with an added mate screen protector, to reduce light reflection on that glossy screen: less reflection means less need to put brightness at max = even better autonomy). A secondhand M1 Air would be great and a lot cheaper too than a newer one (and you won’t miss much from the newer models if you’re doing digital photo on the go).
+1 Depends the use case.