Hey Charles. There is a lot of competition for good deals out there but the good news is that new deals are constantly coming up.
A pre-qualification letter is pretty standard so it won’t help you stand out. It’s more of a requirement than a bonus if you are financing the acquisition. And if the competition makes a similar all cash offer it’s going to be difficult to compete.
Most wholesalers have lists of cash buyers. They’re similar to traditional sellers in that if a cash buyer makes an offer on their deal it’s going to stand out and be more palatable than a financed offer (assuming similar offers).
If I were you I would strongly urge you to make connections with hard money lenders who can get you cash in 10-14 days so you can close quickly to compete. You can then refinance on the back end with some more permanent lower interest financing (assuming you buy a good deal).
As for where to find deals there are countless articles and podcasts on BP regarding this. (FSBO, FRBO, Wholesalers, pre-foreclosures, etc)