AE or PR?

After Effects is a terrible video editor. Edit first, use AE only for those shots you cannot produce in Premiere Pro. I would strongly suggest that you learn about the Essential Graphics Panel and MOGRTS for all of your titling and animated graphics needs. You will only have to create one animation, then you can change all of the text in Premiere Pro. 

If you are going to create subtitles for the whole project that is another completely different workflow and often, a subtitle text document and a different app or even the YouTube tools are much more efficient. 

There will be a great temptation to import the entire Premiere Pro sequence into After Effects and do all the graphics, text, and image animation in the new comp but that is almost always more tedious and time-consuming than editing in Premiere Pro and then working on just the shots you need to work on one at a time in a separate comp in AE. 

Most of my AE work is on shots for films that are thirty minutes or longer. 90% of my comps are less than 7 seconds long and maybe one comp out of 50 has more than one shot. Some comps even have only a portion of one shot. I did one not too long ago that was only a few frames cut of a long shot so put some cloud to ground lightning behind a cowboy riding a horse. 

I hope that makes sense.