While that would traditionally be true, it's worth noting that most of the managers we were linked with to replace Ten Hag have played some variation of three at the back previously, either some or all of the time. Amorim, Tuchel, Frank, Alonso, Inzaghi, Southgate, Naglesmann, etc. Plus other managers who weren't linked to us, like Glasner at Palace or Gasperini at Atalanta.
And that's not counting rarer, more infrequent uses of the formation for specific games too. As per an article on the Premier League's website, "only five of 20 Premier League clubs did not start a single match with a three-man defence in 2023/24".