Why are some seemingly basic things so complicated in QB? (new user, trying to get set up/purge account)

I'm an Amazon/ebay seller who is trying to get set up w/ QB after the ending of GoDaddy book keeping. I've spent a number of hours trying to get set up correctly after subscribing to QBO Plus. 

After initially transferring everything from GoDaddy using the tool, I quickly realized that was a mistake and researched how to start over, and then purged company. 

I spent a lot of time playing around importing accounts. I did another purge at some point. I never saw the text in the QB help files that basically said doing a purge could be dangerous in that it may break any bank connections you set up going forward. This was NOT mentioned in the various forum posts on purging. Sure enough, it seemed to break my Chase connection, even after going on the chase side and removing the connection, it will not correctly sync anymore. After that frustration, I just decided that I'd manually upload all credit card transactions periodically and only connect my checking and sales channels since those seemed to be working.

After another "purge," I noticed the Amazon and Ebay transactions are still listed under the "app transactions." Even after going into "my apps" and disconnecting those, and doing another purge, all those transactions are STILL in the banking section.

WHAT is the point of the purge function if it doesn't actually give you a clean slate?? I believe I've played around enough, relearning the double entry system and QBs in general from using it years ago, after years of using the more simplistic GoDaddy service, and would like to continue, but it is seemingly impossible since once you do a purge it seems to break your account.