Kyoto is gonna be a blast but yeah those crowds near kiyomizu-dera are no joke... you definitely dont want to be fumbling with lens caps there. since youre used to primes you might be worried about quality but honestly zooms have come a long way. if i were in your shoes i would look at the Sony FE 24-105mm f/4 G OSS. it is basically the gold standard for a safe, reliable travel lens for a few reasons:

• the focal range is super versatile. 24mm is wide enough for the grand temples and 105mm lets you snag those candid street shots without being intrusive
• it has built in stabilization which is a lifesaver when youre shooting inside dim shrines where you cant use a tripod
• being native sony glass the autofocus is just snappy and reliable... no weird hunting or firmware issues to stress about on your vacation another solid but slightly riskier pick is the Sigma 24-70mm f/2.8 DG DN Art. it gives you that f2.8 blur you might miss from your primes but its quite a bit heavier to lug around all day. personally i value the extra reach and the lighter weight of the f4 for travel. it stays plenty sharp for an a7iii sensor so i dont think you will be disappointed with the results at all. its a solid choice if you want to keep things simple and safe.