Pretty sure TSN is unrelated to ATM determinism, and comes from a completely separate area (replacing custom field buses where timing and contention is more important than bandwidth). Some of ATM complexity came from wanting to deliver the same quality of experience as plesiosynchronous networks provided for voice (that's how it got the weird cell size).

Once those requirements dropped down (partially because people just started to accept weird echo) the replacement became MPLS and whatever you can send IP over where Ethernet sometimes shows as package around the IP frame but has little relation to Ethernet otherwise.