The company has done something like 50 dives. Not all to the titanic but some. There is some fog around the dive vessels. The one they promote is a carbon tube but apparently it started suffering fatigue damage (as predicted by the fired manager) and was replaced with a different carbon tube. I have seen a report that the submersible they are in is not the carbon tube one. I have no idea how many they have or what the construction differences are.
As for cable and winch, I don't know. Seems like a useful addition but may be infeasible. You are talking about a cable more than 4km long to recover a vessel that weighs 23000 lbs (in air). Add in a bunch of drag and the force numbers are pretty high. I think your bigger problem would be trying to get the cable near the sub. Kilometers of cable has lots of drag and currents will be going in many different directions in the column. Maybe surmountable by having multiple cables of increasing diameter. Conceptually, ROV hooks centre of 10 km loop of braided fishing line onto large pulley on sub and then surfaces with line paying out behind. Surface ship grabs fishing line and uses it to pull something stronger through the pulley. Stronger line then has enough snot to pull lifting line through the pulley. Then you hoist (ideally deploy a clamp on the sub so lines become redundant prior to lifting).
Listening to previous reports of lost communication every dive, unable to find the titanic, emergency surfacing, etc. This company has been a crapshow from the beginning and wasn't getting better. CEO and investor money are now gone and I can't see the company continuing. Another asshat "CEO" will come up with a way to bilk billionaires soon enough.