Some of the ports you mentioned are already available: Quake 1 & 2, eDuke32.
I've found a handy Google Drive share with about every OPK ever released : https://drive.google.com/drive/folders/1gF5AHpe5V-o-G9FyzrhFJ2oTPBSBke50
You also have chocolate-doom, Hexen 2 and other game ports such as Cave Story, Reminiscence.
I know. I own an LDK. Those are pretty much the games already available on LDK and RS-97.
On LDK Quake 2 and Duke 3D can't play properly since it only have 6 buttons.
Only up to Quake 1 is playable on LDK.
On this thing however, 12 buttons should be feasible to experience those games fully.
Chocolate-doom can't run brutal doom. I don't know whether it's feasible on these kind of device or not, but hey brutal doom on the go is a wet dream come true.
Blood port should be sweet, somebody mention it awhile ago, it already have pi port, so it should be able to be ported onto this.
Descent-dxx however, isn't ported to "modern dingux" yet.