I can confirm the 870 DETENT STAKING PUNCH works. Here are the parts that were needed.
https://www.brownells.com/tools-cleaning/gun-tools/shotgun-tools/870-detent-staking-punch/
https://www.midwestgunworks.com/product-display.html?Product_Code=70096
https://www.midwestgunworks.com/product-display.html?Product_Code=70097
Once I had everything, I removed the barrel and held it vertical with the end pressed up on a wood floor. A padded vice would be more logical but didn't have one. I then held the 870 punch and pressed the detent and spring down. I gave 2 light smacks with a metal hammer and it was enough to keep the detent down so I stopped there. Probably should go a little harder since the factory looks like they moved way more metal than I did, but its holding up so far and works as intended. This was a cheap solution to fix it yourself instead of having to ship out the barrel/gun for an RMA.
Big thanks to the guy who thought of the 870 tool!