I got Deepin to output 2560x1440 from above mini-ITX PC to my QHD monitor using custom resolution hack from:
https://www.notebookcheck.net/2560x1440-or-2560x1600-via-HDMI.92840.0.html
xrandr --newmode "2560x1440" 220.812 2560 2608 2640 2720 1440 1443 1448 1478 -hsync -vsync
and activate it as usual with
xrandr --addmode HDMI2 "2560x1440"
What the heck? Who wrote this? When I typed in the second line, I get error output not found. Nearly gave up, then went to display in control panel and saw display was using "HDMI-1". replaced the HDMI2 with that and it worked!
I assembled a mini-ITX from parts found on Aliexpress for $200 USD total (minus the display and keyboard and mouse of course).
This is the motherboard I used:
https://www.aliexpress.us/item/3256803923167202.html
This system works like a GEM on Deepin 20.7! The reason I chose the 3rd gen Intel Core i5 motherboard is because I want this computer to run anything from Window XP, 7, 8, up to 10 (and possibly 11 too).
OMG, upon fresh install of Deepin 20.7 to multi-boot along side Windows 7 and XP, I wasn't expecting much. After all this type of computer came out in 2012/2013 so should be considered pretty out-dated but still plenty useful.
I was surprised the sound works just like that. Also what surprised me even more, I plug in a Wifi 4 USB dongle made by Belkin. It's even using draft version of WiFi 4 (not completed finalized version) and works just like that.
I had problems with Deepin 20.7 on Huawei Matebook D 15 (2021 version). The sound doesn't work only Bluetooth sound to headset, but the wifi is fine. Deepin 20.7 certainly works like a charm on my newly assembled mini-ITX PC!
I need to evualate more/other USB wifi dongles on this system to see if they work with Deepin 20.7 without needing drivers, but OMG WiFi4 (draft version) from some obscure manufacturer working like that without drivers? It's unbelieveable!