Locking torque converter autos have been around for many years now. The two double clutch autos I’ve had (Skoda Suoerb and Kia) both exhibited less smooth response at slow manoeuvres than did my CVTs or right foot/left foot/handbrake on a manual. Although the advent of EPB makes the manual approach a bit less controlled.
E-CVT….. The clues is in the “E”. Here’s a link explaining the Toyota approach. If you search CVT wikedia it’s surprising how many different types and applications there are. I once worked on a Hunt class MCMV. The Slow Speed Drive used when minehunting was a CVT. it comprised Dowty hydraulic swashplate pumps driven by a diesel and hydraulic motors on the driveline. By varying the engine speed or swashplate angle the drive could be very accurately controlled. I wouldn’t recommend it for cars though.
en.wikipedia.org
This is the best working model description of how the eCVT works. Hybrid Power Split Device. eCVT transmission. - YouTube He mentions "Ford" but the eCVT is the same as Toyota's
www.toyotanation.com