I actually think the ideal kickoff is one that's hit high and lands one yard deep into the endzone. Because returners will bring that out almost every time and you should have a good shot to pin someone inside their 20.
Zuerlein was obviously a really good kicker overall and on kickoffs. But his touchback percentage wasn't THAT much greater in his prime (66.2% from 2013-2018) than what the Rams are getting this year (56%). It's that the kickoffs lack some height
and that the coverage units have been poor. As much as the Rams are playing with the kicker spot I would hope they are also making some changes to the 10 other guys running down there.