I use Aegisub for doing all my captions, closed captions or open captions. After a bit of practice adding and timing captions can be done quite quickly. There are many other functions in Aegisub that I don’t use or haven’t even explored yet.
Here is an introduction to a video tutorial I made a while back. The full tutorial, more than 25 minutes is available from our shop for $7.50
It is at the bottom of the https://gaijin-eyes.com/products-page/ page.