I struggled with the weight of the camera too. It is a beast to carry around for more than an hour. I decided to be cautious and went with a more reliable setup because I was worried about the hot shoe getting damaged by a loose-fitting part. Here are a few things to consider for your trip:

• The Leica Thumb Support SL2 19634 is undeniably expensive, but it offers the most secure fit. Since it matches the camera frame exactly, there is zero risk of it wobbling or putting uneven pressure on the hot shoe rails. For a trip where you are walking all day, that peace of mind is worth something.
• If you want a mid-range alternative, the Haoge THB-LS Thumb Up Grip for Leica SL2 SL2-S is a solid choice. It is machined from aluminum and fits better than the generic $15 options. It doesnt block the rear dial, which is a major win for ergonomics.
• Make sure whatever you buy has a rubber contact point. This prevents the metal from scratching the camera body and helps keep it from sliding out when you are sweating in the heat. I honestly think the Haoge is the best compromise if the Leica one is too pricey. It feels sturdy enough to support the weight of the camera without feeling like it is gonna snap. It is a decent option for street photography where you need to be quick.

Re: "I struggled with the weight..." - yeah it's heavy. Be careful with those cheap $15 ones though. I'd suggest:

• Haoge THB-LS Metal Thumb Up Grip It feels way more solid.