Sign in to YouTube
Click your profile icon
Select YouTube Studio
In the left menu, click Content
Click Published or use the search/filter to find your videos
To view channels you subscribe to: click Subscriptions in the left menu (or on the left sidebar)
To view your subscribers: in YouTube Studio, click Analytics
In Analytics, open the Overview or Audience section
In the left menu, click Subscribers (if shown) or use the Audience tab to locate your subscriber count
To view subscriber activity: in YouTube Studio, click Analytics, then Audience, then Subscribers (if available)