You can never have too many 50s.
🙂
If you want Zeiss pop/contrast, then IMO it's a Planar, such as the 50/2, but perhaps even better is getting a G45/2 converted to M-mount. That lens IMO is sharper and bolder than the 50/2, but has a 6-bladed aperture, meaning not so pleasant rendering of OOF specular highlights when stopped down.
That said, I'm not sure trying to emulate what you achieved, rendering wise, with the Hasselblad is the best path to take with the Leica. There are so many 50 options available, so why try to force the smaller format to emulate something else?
You'll not find much love of the modern Leica glass here due to its direction towards technical perfection, but if the budget allowed, I would suggest trying the 50 Lux ASPH because wide open at nearer distances it's got a good balance of soft/sharp thanks to some SA. And if you like super creamy/smooth background rendering, it's got some of the most Gaussian rendering available in an M-mount 50, IMO. Sure, stop it down past f/2 and it becomes higher contrast and high sharpness, which can be useful, too. Close to it is the Voigtlander 50/1.5, either version. The Voigtlander is actually a bit sharper centrally wide open with slightly less smooth background rendering and a bit more moderate overall contrast (the current version has improved coatings which may achieve higher contrast). But across the frame the Lux ASPH is better once stopped down a bit.
For more character and less predictability (the ZM 50/2 is a very predictable and easy to use lens), go for the C-Sonnar. I'm a big fan of Sonnar rendering. It can be a bit wild wide open (which can be fun) and calms down and smooths out nicely, stopped down a little. Background rendering retains a nice degree of structure without being overly busy. The C-Sonnar would be the most 'technically perfect' 50 Sonnar option (in M-mount) due to modern coatings resulting in greater color saturation, contrast, etc. My Sonnar heart lies more with the older versions, such as the post-war Opton-Sonnar (not sure these are available in M-mount - you may have to buy the typically found Contax RF mount and use an adapter), but there's also the Canon 50/1.5 and the very funky Nikkor 50/1.4, which can be found in LTM, though the Nikon mount version is much more common. That lens has a big dual-personality swing between f/1.4 and f/2 contrast/sharpness/rendering changes.
I also like the 50 Cron Rigid. It sits between modern and vintage. It's not as wild as some of the earlier 50s, but has a very pleasing (to me) look wide open. Stopped down and it's sharp, only giving up some contrast to modern options. Similar can be said of the Canon 50/1.4 LTM and Canon 35/2 LTM. There's enough vintage character wide open to make them interesting, but stopped down a bit and they're very sharp, just lacking a bit of saturation compared to modern coatings. But IMO, their slightly muted color rendering reminds me of 60s-70s era color photography. The 35/2 is also tiny, if perhaps a bit on the delicate/fragile feeling side.
I did a boring but hopefully informative foliage rendering comparison of many of these 50mm lenses (and the Voigtlander 40/1.4)
here. At the bottom of the page is a link to higher rez downloads. Yes, these were shot on digital... and unfortunately at the time I didn't have, or have access to the ZM 50/1.5 or 50 Cron Rigid.
