Agree on the extra power. For trekking Tuscany, I have been very satisfied with these additions:

• SanDisk Extreme PRO 128GB UHS-II SDXC for fast buffering
• Peak Design Leash Camera Strap for lightweight carry

Protecting your expensive gear is everything!! I highly recommend getting the Leica Hybrid Glass Screen Protector Q3 to keep that display safe from scratches while you're out hiking. It's a total lifesaver! Also, definitely grab an extra Leica BP-SCL6 Li-Ion Battery so you dont run out of power in the middle of Tuscany. You're gonna love it there, such an amazing trip!

I've been extremely satisfied with a minimalist approach for hiking. Since you're worried about that half case blocking the battery door, just skip it. A high-quality filter is a better way to protect the 28mm Summilux glass without adding weight. The B+W 49mm Master 007 Clear Filter MRC Nano is great because it uses Schott glass and doesn't mess with your image resolution. A few other things that work well for me:

• Haoge THB-Q3B Metal Thumb Grip for Leica Q3
• It slots into the hot shoe and gives way more stability when you're shooting one-handed on those uneven Tuscany trails.
• Anker 735 Charger GaNPrime 65W
• Since the Q3 supports USB-C Power Delivery, you can just plug it in during lunch to top off. Honestly, this setup keeps the kit light and well under your budget... let me know if you need more technical specs on the charging!