I've got a NAS I built some time back with (originally) a Pi B and 2x salvaged 3.5" HDD. I used some ebay USB2 to SATA adaptors, and it was powered with a separate 5volt and 12 volt supply.
Over the years it's been tweaked and upgraded, ended up being a Pi 2 B+ with same USB adaptors, power from buck/boost converters to give 5v & 12v from a ~11 - 13 volt solar charged battery.
Recently it's been showing its age and I suspect a drive or possibly the USB > SATA adaptor failing. Going to rebuild it, using some 2.5" drives that I've already got and will eliminate the need for 12 volts. Also likely to move it to Pi4 for better data throughput.
I'm after suggestions for USB3 to SATA adaptors that work reliably with the Pi4, give reasonable performance, ideally don't get in the way of SMART on the drives (some of the adaptors I'd tried in the past didn't like smartctl) but aren't excessively expensive.
2.5" HDD enclosures aren't really a solution as they rely on the USB for power. I want to provide my own power to the drive, and have a separate SATA to USB link to the pi.
Suggestions very welcome as to what may have worked well for you.