A phrase is doable, especially paired with customized comments.
This is the strategy that I use, and the comments usually don't get deleted.
But when you pair it with a live link, you're posting spam.
It's only a matter of time until you get shut down.
But if you're looking to post bulk YouTube comments, the going rate is like pennies each.
It's pretty straightforward.
What you should look for is some level of customization.
You can't just be somebody posting the same phrase over and over.
That account is gonna get banned.
You need one or two sentences that let the viewer know that the commenter actually viewed the video and is actually commenting on what's going on in the video.
This ensures that your brand or message survives and can become a passive source of traffic.