The OnLogic Helix HX500 Review: A Rugged Fanless 35W Mini-PC

I see nothing special there. Not even "rugged". Get a

[1] https://streacom.com/products/db1-fanless-mini-itx-case/

and the fitting

[2] https://streacom.com/products/nano90-fanless-psu/

and put any Mini-ITX with APU/CPU & IGP up to 45W in there, add RAM/SO-DIMM, SSD, be done with it.

If you want to be super obsessive about it, specify the exaxt fitting PICO-PSU

[3] https://www.mini-box.com/s.nl/it.A/id.417/.f

or clone thereof, choose your own fitting power-brick with G-AN from Anker/Aukey/Leicke/Kami/Kaze/Peng/Huy/AND/SOON...

you'd probably have something better, or very similar for less money, but more time.