My question is very similar to this one, I want to get channel id using channel custom name.
The answer on the question mentioned above which is:
GET https://www.googleapis.com/youtube/v3/search?part=id%2Csnippet&q=annacavalli&type=channel&key={YOUR_API_KEY}
doesn't work on small channels, for ex. when I run it with this channel: https://www.youtube.com/AnnaShearerfashionfettish it returns nothing.