There are quite a few but none are super active.

Mine is pretty basic but is built on the shoulders of giants. Also that $20 was from pre-pandemic / pre-chip shortage prices. I’m guessing it’s more like $35 now, or maybe high $20s from ali express.

I use Home Assistant for home automation. It has a now official addon called ESPHome for easily configuring esp devices and adding them to Home Assistant.

I bought some cheap dev boards off amazon and thankfully they worked
    an esp8266 microcontroller with IC2 headers and a microusb port already onboard
    a bmp280 that measures temp, humidity, and barometric pressure
    a lux sensor with a plastic dome over the top
I soldered them together on a prototyping board

All the components were supported by esphome, so I just needed to write the device config and then flash the devboard via esphome (in a web browser) over the built in usb.

I 3d printed a housing for it, but you can also buy boxes. It needs airflow but also needs to stay dry. You can use a spray sealant to help avoid corrosion from ambient humidity. I skipped that step because I want to see how quickly it becomes problematic… and I should probably check on that.

https://www.amazon.com/Springfield-Wireless-Comfort-Thermometer-5279298/dp/B091C9J7XK?ref_=ast_sto_dp

Same. I'm lucky for software to be my hobby/career. It's practically free. Contrary to popular misconception, it doesn't require any kind of special or more powerful hardware (for most dev, at least). Maybe $150 for a second monitor, for sanity, but that's not actually necessary.

...I mean, I do have good hardware too, but that's for my gaming hobby, not my software hobby.

Can you recommend any good soldering gear for an intermediate level? I've done plenty of soldering over the years but have always used crappy low end products. It's always been a struggle to properly do a clean-true solder (not just heating the solder like I see everywhere) even though I try to meticulously maintain my equipment. I'm hoping that it's just the equipment I use and a higher end one will make things a breeze like I see the professional's use.

It's really a pain in my ass. On top of maintaining the equipment I have whole setups I've constructed to hold wires and equipment snugly so I can properly apply heat. I purchased a high temp kit but it's cheap as well and still sometimes run into the same problem, with the smaller components and projects though I'm afraid to use it and overheat something that can't handle it.

I haven't bought an oscilloscope yet either, but I keep window shopping.

My next project is to make an oscilloscope clock

This sounds like the point where you dive into the next rabbit hole of making enclures. At least I could see that happening.

I'm looking to make some wooden enclosures for some things myself.

My next step is custom boards and smds, and an oscilloscope seems like a good way to diagnose when reflow goes wrong. I already have had some fights with I2C using dev boards. But really I'm eyeing one because I have allusions about doing fine calibration on analog sensors.

I should add that I've been talking myself out of an oscilloscope for 2+ years now. I don't REALLY need one.

https://www.sainsmart.com/products/sainsmart-dds-140-40m-200m-s-virtual-oscilloscope-logic-analyzer