Shade cloth could be an option along with a temperature sensor that vents air via a fan from the top of the room could work to protect against the worst heat of the day. That and lots of watering.

Why? Can't you get natto from an Asian store?

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I've made it dozens of times always starting with frozen natto, and never had any issues. I like to use organic black soybeans, because they are even more nutritious than regular soybeans. I use an old ice chest, with a seed starting mat plugged into an Inkbird temperature controller, with a pyrex baking dish on top of the mat with warm water in it. Then the inoculated beans go on top of the warm water pyrex. That keeps the temps constant.

Hi are you by any chance referring to this? https://www.amazon.com/dp/B01HXM5UAC/ref=asc_df_B01HXM5UAC5114756/?tag=hyprod-20&creative=395033&creativeASIN=B01HXM5UAC&linkCode=df0&hvadid=198101685250&hvpos=1o1&hvnetw=g&hvrand=2806952839949716824&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9060374&hvtargid=pla-318107594620

It seems like they're used for terrariums and plants? I do have a crockpot and im actually pretty intrigued.

This is definitely what you want! Just want to add that the dome you want is one that's ceramic at the base. They're rated for the CHE bulbs. I recommend this dome, along with an Inkbird thermostat. Your CHE bulbs are widely available. 100w or 150w would work. Just check to make sure the dome is rated high enough for the bulbs. It doesn't matter what color bulb you pick as long as it's a ceramic heat emitter bulb. White and black are common.

They have temp controllers for about $20 on Amazon. You just set the temp you want it at and then plug your heat mat into it and it will regulate the temp.

https://www.amazon.com/Inkbird-Max-1200W-Temperature-Controller-Greenhouse/dp/B01HXM5UAC/ref=mp_s_a_1_5?keywords=Thermostat+Control&qid=1679680325&sr=8-5

These are great for temperature control: https://www.amazon.com/Inkbird-Max-1200W-Temperature-Controller-Greenhouse/dp/B01HXM5UAC

I have one for controlling beer fermentation temperature and it works very well and is easy to use. Pug your fan into the cooling socket and a small heater of sorts to the heating socket. Depending on the temperatures OP is dealing with I would recommend a seed warming mat (used to keep seeds warm for germination) in the cage but not with the batteries directly resting on them. They provide a gentle 20w of heat spread out well but they will get hot if you put something directly on them and the heat can't escape.

https://www.amazon.com/dp/B01J1E5LWM?ref=ppx_pop_mob_ap_share

https://www.amazon.com/dp/B01HXM5UAC?ref=ppx_pop_mob_ap_share

I use this controlled by this. I printed an adapter for my resin printer to raise the cover a bit and provide cord access to the space, but it works beautifully.

Just something like this clipped to the side, with a temperature control circuit like this to keep it from running too hot.

If the danby doesn't have a fan on the evaporator, you can control the temperature with something like an Inkbird. Set the dial to all the way cold, and plug the kegerator in to the "cooling" outlet on the Inkbird:

https://www.amazon.com/Inkbird-Max-1200W-Temperature-Controller-Greenhouse/dp/B01HXM5UAC

If the T-stat is defective, you may have to bypass the T-stat.

However, there are other things than cause the foaming...

1. what is the actual beer temperature as it comes from the faucet?
2. Is there breakout or bubbles forming in the liquid line coming from the keg coupler (or liquid disconnect if you use corny kegs)?
3. What pressure are you serving at?