Don’t treat your to-watch or to-read list as a to do list, treat it as a filter. Instead of reading/watching something, you put it onto your list, and occasionally, you go through that list and delete the items which seem least valuable/exciting/etc.
That way, you are reducing the amount of stuff you read/watch, and you are increasing the average quality/value of things you consume.
And you don’t pile up stuff, even if you tend to over-collect.