I also had a problem with Anaconda Navigator, starting from a long time (5-10 minutes) on my Windows 10 machine. After defining the proxy settings in the .condarc file and OS ENV variable, it decreased to 1-1.5 minutes. See if this works for you :).
Changes to the .condarc File
proxy_servers: http: http:
Update OS ENV variable as:
HTTP_PROXY= http://yourhttpproxy:port HTTPS_PROXY = https://yourhttpsproxy:port
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