A unified calendar for Windows and Android#99

A unified calendar for Windows and Android would be great. Windows calendar sucks and an alternative from Newton would be great, especially if you manage multiple accounts. For example, I manage 6 different mail accounts, some of them are gmail, others from zoho, a third from a third-party etc. Gmail accounts work fine but the others not, so I can’t have all of my appointments on a unified calendar, which is a bit frustrating.