Dear Xipper and WeatherCat cost benefit analyzers,
Perhaps the first question you should ask is exactly what is the cost to you of running your Mac Pro. It wasn't that long ago that 100 watts was a standard light bulb. While 10 watts is 1/10 the power consumption, what really matters to you is what difference does that make for your life. You can get your power consumption from any monthly bill. Would eliminating that one computer ultimately made all that much of a difference? Before you send any money on a hardware upgrade, how many months/years of running that computer would be required to pay for the upgrade?
It isn't as academic as it might seem. Silicon labs might well update their driver given enough time. Is it worth the effort to shuffle all you have now when time could be on your side?
What is the cost/benefit of any of this, I'm not a paid meteorologist

In this case, I have the replacement Mac in hand and everything but Weathercat was migrated in the background while I was working for the day job on my laptop. The upgrade isn't just driven by the power savings, that is a nice side bonus. I pay about 16-cents per kWh, so the Mac Pro costs about 55-75 cents per day to operate and it turns out the mini even uses less (typically using just 5W!) and the Mac Pro actually uses more than I had estimated. It averages to >$200 energy savings annually will be a nice benefit, reducing the heat load in my office in the summer months will be even more so. I was also just able to sell the Mac Pro for most of the cost of the Mac mini, so at this point the power savings are just lining my pocket with benefit in the cost/benefit ratio
The actual "pay back" in energy savings will be far less than the lifespan of the hardware, it also makes my UPS have a longer runtime as another bonus...as the UPS will now run dead from its internal drain faster than the mini will draw energy out.
Sorry, not everyone has been able to keep up with Apple's rate of progress. Like so many other things these days, such are the conditions that prevail.
SiLabs has always been less than reliable for driver support, it just too bad Davis went with the SiLabs serial port rather than one of the many lower cost and more reliable options that have broader support (e.g. FTDI).
I ended up ordering a 3rd party logger and will have it after Christmas, my weather station will just be offline until then and I won't lose any sleep over it as there is zero payback on the weather station or the hardware, I also need replacement batteries for the station that won't arrive for a few days so the unreliability aligns with it being down anyhow 🤷♂️ If I can't get it to work with Weathercat I will just accept it and move on, and utilize Wunderground for my historical data. I will share if it "works" to help others that encounter this issue which was the intent of starting the thread 😉