Man, I totally feel you on the 50mm Lux. It is a beast of a lens but yeah, lugging that around London all day... no thanks. My neck started hurting just reading your post lol. Switched things up recently and honestly, I couldn't be more satisfied with the Leica 28mm f/2.8 Elmarit-M ASPH. for my M11. It is tiny. Like, basically a pancake lens compared to the Lux. The weight difference is night and day and it balances so well on the M11 body. Usually I just throw it in a small bag or keep it on a thin strap and barely notice it's there. That 28mm focal length is just perfect for street stuff because you get that wider perspective for architecture and busy crowds. Tbh, it has been my go-to for months now and I have zero complaints about the sharpness or the way it renders colors. If you want to save even more cash and go even lighter, you might wanna look at the Voigtlander 35mm f/2 Ultron Vintage Line Aspherical VM. It is ridiculous how light that thing is and the image quality is super punchy. Both are solid, but the Elmarit stays on the camera 90% of the time. You can easily find a used Elmarit for well under your 2k budget, leaving you some extra money for some travel or a nice dinner. Just stick with it, you are gonna love how much more agile the camera feels once that weight is gone... shooting should be fun not a workout!

^ This. I've tried many, but the Voigtlander 28mm f/2.8 Color-Skopar VM II is my pick. Its tiny, cheap, built like a tank, and way less likely to get nicked in London.

@Reply #2 - good point! Zeiss glass is amazing but for real-world street stuff where you just want something light and cheap, I have been super satisfied with the Voigtlander 35mm f/1.4 Nokton Classic II MC. Ngl I was worried the 60MP sensor on the M11 would expose every flaw but the character of this lens is just perfect for that London street vibe. It weighs basically nothing compared to that 50mm beast you have. You should definitely check out the Phillip Reeve blog or the Fred Miranda Leica forum if you want to see raw samples. Those sites are literal gold for comparing M-mount glass without the marketing fluff. Honestly, saving that money for a weekend trip to actually use the camera is way more practical than overspending on a lens that just sits in a drawer. No complaints here at all.

Regarding what #1 said about feeling that 50mm weight, tbh I totally agree! Check these specs:

• Zeiss Biogon T* 35mm f/2.8 ZM is only 200g!
• Fantastic MTF resolution and zero distortion!

To add to the point above: i totally get why everyone is pointing you toward those other brands, they are fantastic for the price, but honestly i think youre gonna miss that specific Leica look if you jump ship! I remember back in my early days wandering around with a massive setup, thinking i was some big shot pro... my neck was absolutely killing me by noon every single day. Then i tried some older, smaller Leica glass and it literally changed everything for me! I love the character you get from the older stuff. Seriously, just look for any of the more compact, older lenses from Leica themselves. You can find some amazing deals on their vintage stuff that fits way under your budget and weighs next to nothing. The colors and the way they render on that M11 sensor is just... chefs kiss. Stick with the brand, you wont regret it! Ngl, the third party stuff is fine but nothing beats the original glass on an M body.