ntp has been replaced by ntpsec in Debian. (I am the Debian ntpsec package maintainer.) By default, NTPsec on Debian uses the NTP Pool, so no NTS. But NTPsec does support NTS if you are running your own server and supports it opt-in on the client side.
As far as I know, the Debian “default” is systemd-timesyncd. That is what you get out of the box. (Though, honestly, I automate most of my Linux installs, so I don’t interact with a stock install very often.) AFAIK, systemd-timesyncd does not support NTS at all.
Doing NTS on a pool would be quite complicated. The easy way is to share the same key across the pool. That is obviously not workable when pool servers are run by different people. The other way would be to have an another out-of-band protocol where the pool NTP servers share their key with the centralized pool NTS-KE servers. Nobody has built that, and it’s non-trivial.