Refrigator not cooling properly, freezer works fine
I'll assume you don't have much food/items in the freezer section. Because you have the fridge set on the max cooling setting and the freezer set higher than the mid setting, it could be that you have frozen the cold air passage from the freezer to the fridge.
If you can, 1) remove all contents that would spoil; 2) turn off the fridge 3) open both doors and allow the fridge to manually thaw out completely (this will speed up the opening of the cold air exchange passage between the freezer and fridge, which is likely blocked and frozen solid. Have plenty of towels handy to soak up the water from the defrosting process,
After a FULL day of being left off and doors open to thaw out, check for any further thawing and dripping water inside, if present wait another 8 hours (you really want to get it thawed out the first time!) When that's done, reset BOTH temperature controls to the factory mid-point setting (5?) as marked on your control knobs.
The key to having a refridgerator run properly is to allow for it to run at the factory settings for at least 24 hours BEFORE you adjust the controls higher and/or lower for each section. Adjust it up or down in ONLY 1 setting increments so as to not cause ice build-up and freezing of the internal air exchange passages.
Also, as you've relegated this fridge as a garage "beer & backup" unit, make sure to keep the freezer as full as possible to make it run as efficiently as possible. You can freeze jugs of water and pack it with cheap thrift store bread to help it run correctly. An empty freezer has to work harder to keep just air at freezing temps. As such, it will pass much colder air into the fridge, and cause these types of freeze ups. By the way, turning up the temp controls only makes it worse and just results in a total "freeze up" inside the cabinet panels that you can't easily see or get at to rectify, hence the reason to shut it off and let it fully defrost.
When you're done, you should have your fridge back in action working like it should, but remember, don't rush temperature adjustments, even thou we all want those frosty beverages, it'll take a couple of days to achieve the desired "chill" you're likely used to getting when it was your primary fridge.
Hope this helps and Best Regards! Semper Fi!