The spread of Buddhism or Confucianism to Europe isn't going to erase beliefs in deities in Europe. If anything, this Europe will resemble China and Japan, with Buddhist or Confucian principles practiced alongside local folk religions (deriving from paganism). Just as many so-called irreligious Chinese keep shrines to Cai Shen, Zao Shen, Guanyin, or Mazu in their homes, you'd have Germans with hearth shrines to their kobolds, English with cofgods, Russians with domovoi, and Italians with whatever the lares would evolve into, just as Christian Europeans continued to hold such folk beliefs in household spirits. You'd have shrines to ancestors and maybe city gods, and sacred groves and other temples. The casual nature of such belief systems (many East Asians believe themselves to have no religion, yet will pray to such shrines if they come across one, and keep shrines to domestic gods and ancestors and practice associated rituals annually) would probably diminish the circumstances that would bring about an Enlightenment like the one in OTL.