Low Power NAS Upgrade

[KFStein]

Budget (including currency): $250 USD

Country: USA

Games, programs or workloads that it will be used for:

• Base OS: unRAID
• VMs: 1 (2CPU/4G today) that handles nginx reverse proxy / fail2ban / offsite backups, 1 (2CPU/2G today) that handles home automation (Home Assistant)
• Dockers: MariaDB, ChannelsDVR, Emby (guest access to family photos and videos), Plex (personal access to media on site and remotely--probably max 1 transcoding stream at a time), freshrss, Wordpress

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at, etc): 

I currently run two servers in a active / standby configuration. They both have Xeon E3-1240v2 CPUs with 32G of RAM and a Seasonic SS-430GM PSU. I recently bought 2 10G SFP+ PCIe 2.0 x4 network cards. While the motherboards use the same C204 chipset, they are slightly different models and in one the 10G card is not recognized. I found a "like new" version of the motherboard that works with the 10G card, and after examining it, it looked like it had never been used. Unfortunately, a little after I installed it and turned on the system, a small fire started around a couple traces on the MB! (All the fans came on, but it never posted, with the fire starting after about 30 seconds.)

The configuration I have now works for what I do and uses around 130W on average per server, (although the backup server only powers on a couple hours a day to synchronize with the primary one and the remote backup site). However, I figure for better hardware support (and available options) I should modernize things somewhat. I'm looking for something that can:

1. At least match my current CPU in performance
2. Consume the least amount of power as possible
3. Use a platform that currently has readily available options in case I need to swap anything out
4. Support 8 SATAII/III drives on-board or with a PCIe expansion card (currently I have 2 SSDs as unRAID cache drives, 4 HDDs for parity / storage, 2 empty HDD slots for future expansion, and one PCIe SATAIII card with 2 ports as the replaced MB only came with 6 SATA ports on board)
5. Have enough PCIe slots for at least the 10G NIC and (most likely) a SATA card, plus additional lanes for maybe a video or other card for transcoding and/or AI-type things (I would like to move all the home automation voice interaction in-house at some point instead of using Echo devices)
6. Support at least 32G RAM

Basically, I figure I need to change the MB, CPU, and RAM. Plus a CPU cooler if the CPU does not come with one. The rest of the parts I can re-use from the existing system. Looking around at similar posts, the AMD 5600G and Intel i3-1x100 CPUs seem to be recommended for low-power NAS usage. But when pricing parts, they both land around $320USD (example AMD build: https://pcpartpicker.com/user/KFStein/saved/#view=dV4c4D). I looked around for some mobile CPU options, but the motherboards I found were all small form-factor with usually a max of 6 SATA ports and 1 PCIe slot. Any other suggestions are welcome!