Honestly, choosing your first real lens can be a bit overwhelming since those numbers dictate everything from light gathering to how far you can zoom. Since you are hitting Japan, you really might want to consider the Tamron 17-70mm f/2.8 Di III-A VC RXD. It has a constant f/2.8 aperture which is crucial for those dimly lit shrines in Kyoto. Be careful with lenses that have variable apertures like f/3.5-5.6 because they get darker as you zoom in, which might force your camera to use a high ISO and make photos grainy. The Tamron also has built-in vibration compensation which helps at slower shutter speeds. It is a bit heavy tho, so make sure your neck strap is comfortable. If you want more versatility for street shots, I would suggest looking at the Sony E 18-135mm f/3.5-5.6 OSS. It covers a massive 7.5x zoom range. Just be aware that it doesnt perform nearly as well in low light as a fast f/2.8 lens. Another solid pick is the Sigma 18-50mm f/2.8 DC DN Contemporary. It is incredibly tiny and light, perfect for Tokyo crowds. It lacks the long focal length reach of the Sony, but the f/2.8 helps get that real bokeh your iPhone usually tries to fake with software. Let me know if you want me to dive deeper into the glass specs or MTF charts... it can get pretty technical but you got this.

tbh i was so happy using the Sigma 18-50mm f/2.8 DC DN Contemporary at fushimi inari. its cheap and tiny. tip: carry a spare battery so you dont run out while exploring.

To add to the point above: I once hauled heavy gear through Kyoto and it honestly just slowed me down. Reliability is key for travel. The Sony E 18-135mm f/3.5-5.6 OSS is a very safe, conservative choice. It covers a huge zoom range (the 18-135mm part) and fits your budget. It handles street shots and distant temples without needing a lens swap. TL;DR: The 18-135mm is the safest all-rounder for your budget.