Fish auction

I’m tired of new fish coming in with minor and major diseases even with a 4 week quarantine period and then having to go through the stress of treating them with medication. I’m considering just getting all my fish from auctions at this point because 1. The fish haven’t had to go through a stressful supply chain. 2. The hobbyist breeder usually monitors health more diligently than a wholesaler while also having more accountability if they sell sick fish, and 3. I’ve heard it’s much cheaper. What do you guys think?

Depends on you. I don't have much time to go to auctions, but they're great usually.

Although, if you can find a good LFS that's not a big chain, it works just as well. Mine quarantines all fish before they sell them and they take full accountability if it's their fault, and if you become good friends with the owners you get discounts pretty often lol. If you're getting from PetSmart or PetCo, then try to find a good local fish store. They also have food and supplies.

Online is good sometimes, as long as they're reliable.

I can’t speak for online auctions as you can’t see the fish you’re bidding on properly.
I’d suggest looking for fish clubs within your local area, and beyond if you’re willing to travel, they often hold regular auctions and are great for finding quality fish, many that you might not see much in Lfs, prices are usually pretty reasonable plus you get to spend the day chatting with like minded people and often learn something too and you make good contacts.
I would definitely recommend giving them a go.

When buying from a LFS it's important to hand select every fish you buy.

Inspect the vendors display tank carefully, watching for obvious signs of disease.

Have the store employee feed the fish. Heathy fish should literally attack the food.

Only select the strongest, most vibrant specimens. I almost always buy the bully fish. Lol.

When you quarantine your new fish, keep the water warm, 80 - 82 degrees & well aerated.

The most common disease issue I've encountered are gill flukes. Thats why during quarantine I preventatively medicate Prazipro.

You need to be ready for Ich & Oodinium too. So keep a med such as Ich-X handy.

I don't use Ich meds until symptoms arise. Prazipro is a very mild medication, while other parasite meds are rather harsh.

If you follow these steps, chances are good your new arrivals will survive.