Yeah, depends what you want. Three very different games. You'll be more of a captain in Cold Waters and more of the fun is in seeing all the different enemy platforms, evading torps, attacking enemy formations. In Dangerous Waters, you can manually track contacts in sonar through broadband, narrowband, and active intercept and you can develop manual solutions in TMA. I don't think it's too hard to get into due to age, but I could very much be biased haha
So you have Dangerous Waters, Sub Command, and 688(I) Hunter/Killer from newest to oldest, all made by the same devs. Three campaigns and Dangeorus Waters also has additional campaigns such as Red Storm Rising and Liu Doctrine for even more hours of gameplay. Honestly, you should be able to get all these games cheaply enough. Just get them and try them.
