For me it only exported the last set. The first few times it stalled with an error and I had to restart, but it had deleted comments and not given me a CSV of the ones so far.
In any case, PDS doesn't get everything, because not everything will be displayed on your profile. PDS goes through your New, Hot, Top & Controversial comments, anything that is not displayed in these lists will be missed. I ran it to completion and it said there was nothing left, but I had a couple gilded comments with <50 karma on the gilded tab that were still there, as well as many comment replies to the Top comments it had wiped.
The only way to get everything it seems is to do a GDPR request and use the links in the files you get.
Power Delete Suite doesn't get everything. PDS goes through your New, Hot, Top & Controversial posts and deletes those - however your reddit profile doesn't display every comment there.
For example, I had many comments that were older than 3 months and <50 karma that were still left unchanged after running PDS to completion several times. In particular, replies I'd made to my top comments were still there, while the top comment itself had been deleted. I also had a couple comments in the gilded tab that it had missed.
The only way to get everything is to do a GDPR request to get all the comments with links in a CSV file. Apparently shreddit can take this to clear the comments, however the PDS dev shits on shreddit for requiring you to input your username and password. I haven't yet tried this, but I'm not aware of any other service that uses the GDPR CSV files.