Viltrox is improving at a pretty insane speed over the last few years.
I reviewed their first L-mount lens soon after the first gen Lumix cameras were released, it was a manual focus lens, image quality was really average, pretty chunky size, build quality was a bit rough, it was alright for the price but the expectations for third part lenses were a lot lower back then. Viltrox was also known as a camera accessory company back then, but it was not exactly a camera lens company.
But when I visited their Headquarters in Shenzhen two years ago, I was very impressed. Viltrox obviously has a lot more resources than most brands I visited during the same trip (maybe apart from Hollyland which is absolutely huge!)
Over the last two, three years, apart from their cine/anamorphic lenses, Viltrox has fully transitioned to making autofocus lenses only. Their "pro" lenses are almost as good as some of the best third-party lenses in the market, but cheaper. Their recent 135 1.8 LAB lens is like 95% as good as the Sony 135 GMaster, but much cheaper and with some fancy features that even Sony doesn't have. The only downside is the size/weight but it is still a pretty amazing lens.
Their recent 28mm pancake lens is also very interesting. Autofocus, real pancake size, f/4.5 aperture, good enough image quality, and only US$99! That's really what Lumix should have released with the S9. I've asked Viltrox many times please release that lens in L-mount.
Viltrox is also releasing crazy number of lenses. I think they released around 10 autofocus lenses just in 2024 + other a bunch of manual focus cine and anamorphic lenses. So if they join L-mount, users would have a lot more good quality choices at very affordable price, even if some are overlapping the lineup from Lumix, Sigma.
But don't get too excited about this rumour. I know quite a few brands have been trying to become part of the L-mount alliance for a while but not getting anywhere.
I think some will probably end up create AF L-mount lens without officially joining the L-mount alliance like Meike.