13’ silverado 6.0 alcohol & 172/175 issue

So I’m fairly new to scan tools but starting to grasp the basics.
I have a 13’ silverado 2500hd. Just bought it and after a couple weeks engine light is on. 172/175 rich codes. As it got cold or just after more time, it started to run kinda poorly. Bit of a stumble at take off, then some extended cranking at start.
So I bought a Launch 431+ off Amazon and been resetting the alcohol content and it fixed the issue as best I can tell. I’m just not sure it’s a full 100% fixed but much improvement.
After a couple weeks I started noticing performance decline and check alcohol content (didn’t check just reset first time), and it’s at 35ish %. Fuel is 10% at most I’m sure.
I checked fuel pressure and it’s good. Like 60 at idle. I think like 40-50 at key on engine off, and holds there.

I’ve read that the dealer usually flashes the ECU to fix the alcohol issue, at least as a first step. I’m not sure how I can go about that. I’m guessing I’d have to buy a subscription for a day or so, then learn how to get it done?
I’m planning on subscribing to the premium account here and learning as much as I can. Yet I’d like to fix this as soon as I can, without trying to flash anything without complete confidence in what I’m doing.
The truck came with only one key and fob. I just got a couple OE keys and fobs and I think I can just get the keys copied / cut by a locksmith or the machines at part shops, if I can get someone to break the rules and do it for me.
I’ve read that Canadian trucks need 2 keys to add more, yet read that people have just used 1 with the ‘insert working key, turn to on, then off, then swap for new key quickly, and turn on then off, repeat for additional keys and bobs your uncle’. One guy said he learned 1 key with only having 1 working on hand, and after it said ‘3’rd key successfully learned’.
For the fob, I think I just go into BCM and get it to learn fobs, hold lock & unlock until it beeps. I’m not sure if I have to erase / unlearn fob first tho. Again I have 1 working key and fob (fob is separate from key), and have 2 additional keys and fobs.

I forgot to search for key learning on here, but I did regarding the alcohol. What are the possible culprits of faulty alcohol readings? I think I read GM uses trim data to estimate %.

Anyways, TIA

So I can confirm that learning the keys the way I mentioned above works. I got the keys from a place on the ‘North Coast’, and got my 2013 Chrysler vans fobs from them a couple years ago. Best prices I could find then and now, and their stuff is legit OE. Lots of scammers selling knock offs as OE.
Parts store cut / copied the 2 keys for free. I went and parked by the service bay at the local GM dealership, just in case it locked up with anti-theft.
I’m going to program the fobs tomorrow with my scan tool.

I’ve read that the dealer usually flashes the ECU to fix the alcohol issue, at least as a first step. I’m not sure how I can go about that. I’m guessing I’d have to buy a subscription for a day or so, then learn how to get it done?

To do an ECM software update, you'd need a laptop, a J2534 device and a subscription to GM TDS. Single VIN subscriptions are available for $45. You'll have to check your X431+ user manual to see if it qualifies as a J2534 device. It probably doesn't.

But before all that, I'd suggest pulling your calibration ID's and comparing them to what's listed on GM TIS:

tis2web.service.gm.com/tis2web/

That'll let you know if there is an update available, and what the update addresses if available. If you already have the most up-to-date calibration available, then there's no programming to be done.

Thanks bud. So I’ve checked the calibration numbers and they correspond from scanned data and website.
I didn’t see anything suggesting there was any available updates. I added the individual part numbers and compared the calibration number to what I got from the scan tool and they all match.
Would that tell me the ECM has all the latest updates available?
I guess I have to start looking at what part(s) are throwing the alcohol numbers off. Evap, leaking injector(s), fuel pressure regulator, and intake manifold somehow, are the suspect places to check, according to what I’ve learned.
Thanks so much for the link and info. I looked at an vxdiag for GM that’s just over $100 that apparently will work as a j2534 passthrough, along with a subscription. I’m actually wondering if that would be a reasonable alternative to my x431+, albeit a less convenient one. For the $1000 though I might want to save the money for how often so will actually need one.