You can avoid #YouTube's weird algorithms and broken subscription system by subscribing to channels through RSS instead. You don't need an account, just a feed reader.
Put the channel's username in this address:
https://www.youtube.com/feeds/videos.xml?user=USERNAME
You can then add this RSS address to your feed reader app.
For example, OnePotChefShow's RSS feed is:
https://www.youtube.com/feeds/videos.xml?user=OnePotChefShow
You can also make RSS feeds from channel IDs (strings of letters and numbers):
https://www.youtube.com/feeds/videos.xml?channel_id=CHANNELID