Got the SDRPlay. They cheaped out and provided no USB cable (requires a USB A to B, what used to be a printer cable, and hard to find these days), so had to hunt around for one (and got one at a thrift store).
The good - the device works great with SDRuno - the official and proprietary SDRPlay software. AM came in crystal clear, no noise in the quiet spots and sounded almost as good as my FM signal.
The bad - it doesn't appear to work with OpenWebRX+, my SDR server software. It just fails, no indication of what is happening. I should have expected it, given my previous experiences with this software, but I guess I'm just an idealist. I think you have to be to work with computers, or there would be a lot of smashed ones around.
Anyway, hopefully it's something simple, like updating the driver. Since there's absolutely no documentation with the Docker version (and, in fact, the website erroneously claims that it won't work under Windows), I'll try playing around. Interestingly enough, the cloned SDRPlay I have got further, and managed to initialize before failing (due to the hardware checks SDRPLay uses to detect 'official' devices). It would be a shame not to use it, as the hardware and AM audio works beautifully otherwise.
The fallback plan is to go back to the RTL-SDR V4, which at least works nicely on FM.
An update to my update. The problem is definitely connected to drivers, and the way that OpenWebRX+ uses them. I switched to an older SDRPlay driver, and I was able to receive signals, but with distorted audio. The signals were showing up on the waterfall display, and, as I found with other software, Artisan Radio wasn't overloading the front end, allowing other stations to be received.
There are a number of driver combinations and settings that I have to try to fix the audio. This is going to take some time.
Well, it looks like the Windows SDR version of OpenWebRX+ is limited to the RTL-SDR V4. It works OK for the FM broadcast band, the biggest restriction being its 2Mhz bandwidth.
I managed to get the software to show signals on the waterfall display with the SDRPlay, but the audio is horrible, with lots of underruns. After much experimentation and research, I believe the issue is, basically, the hack of running a Linux program under Windows WSL (Windows Subsystem for Linux) with Docker. There is no native USB interface to WSL, so another hack has to be used to connect the SDRPlay (plugged into a USB port) to the Docker container running in WSL. And that's ultimately the bottleneck - that hack can't keep up with the USB sampling required.
The RTL-SDR V4 is only 8 bit; the SDRPlay is 14 bit. So it requires a lot more sampling bandwidth.
The SDRPlay runs fine with SDRuno under native Windows. That's the 'official' proprietary software for the SDRPlay. So it's working and sounds great with signals on the AM broadcast band.
So here's what I'm going to do. First, I'll get the SDR back up using the RTL-SDR with FM only.
Then, I'm going to bite the bullet and build a Linux computer, install OpenWebRX+ and run it natively under Linux. I'm tired of these hacks. The SDRPlay should then run fine. I guess we'll see.