Continuously losing out to higher bids on homes you had your heart set on sucks, but it's so important to keep your emotions from clouding your logic in the short term. 

Benefits are that you're not 100% on you own, you'll probably get some faster business, you might learn some from an experienced agent, you can see how a team operates, you might see a more disciplined approach to the business and perhaps get to hang out a bit or be in the presence of someone organized.   

Taking out your emotions and focusing on the tasks at hand are imperative to success in this industry.

It is so difficult to separate the math from the emotions at times.

You seem too emotional about this.

Also, hoping it will be easier to refuse to rent to people who claim they have 3 emotional support dogs etc.  

It's important to pull the emotions out of it!

There's ups and downs in REI, can you mental navigate those emotions and not lose focus/control/motivation

(I like to use "families" because it attaches an emotion to the question.

Over time, responsible financial habits will repair your credit.Your goal of 20 paid off homes by 55 is ambitious but doable if you start now, educate yourself, repair your credit, and stay disciplined.