Unfortunately, Digitec and other online shops do not have such an adapter listed. However, if you were to choose another lens that had a Nikon or Canon bayonet, for example, you could adapt it. For slightly less money, there is one that is actually the best lens that could be used with a BMPCC4K: Sigma 18-35mm, f/1.8 DC HSM ART, Canon EF-S

If this lens suits your purposes, I would go for this one. Since it is also about 400 CHF cheaper, you could buy a speed booster for this money (Metabones Speed Booster).
) . It makes a nicer bokehe effect and also a higher light sensitivity. For more detailed information, you could either do some research on the internet or write an answer or question under this comment ;)

Actually wanted to answer^^ Do NOT pay attention to this question

This speed booster here is the best on the market, but costs 800 francs: Metabones Speed Booster

However, if you want a cheaper one, I can tell you an alternative on request :)
I hope it helped you!