Mm2h and number of days in Malaysia

You can stay any length of time. It's a social visit pass valid for 10 years and then renewable. But of course, the usual presence here for more than 182 days applies, in order to become tax-resident.  You would probably need an address if you wanted to get a certificate of residence and then a double taxation treaty certificate.

Malaysia does not tax any earnings that originate from outside the country. The official wording is - income remitted to Malaysia is taxed at 0%. So just getting the MM2H visa would not automatically help you - the German rules about tax-residency will still apply - so I guess you will need to spend 182+ days in beautiful Malaysia (check out Penang Island - which has an active German community - FB Group Malaysian German Society - https://www.facebook.com/MalaysianGermanSociety).

This may also be helpful - it explains that the certificate of residence (COR) is only valid for one year - http://eresidence.hasil.gov.my/indexFAQ_e.php