all you did was hammer out configs

Yeah, that's my point, all the software is there already, with a little bit of persuasion and glue it runs fairly well together. I'm not claiming I wrote actual drivers or whatever. What I did was figured out how to adapt the existing software to work on NixOS, so you can just take your desktop NixOS config, add a couple lines to it, and run it on the phone.

Now you have a phone where half the hardware doesn’t work

All hardware on Librem 5 worked with NixOS as I expected. The reason I'm not dailying it anymore is because the hardware kinda sucks, it's outdated and slow. If I could get the same software stack running on more modern hardware I'd gladly use it. Perhaps the battery life could be improved if the power management was better, but that's about my only complaint software-wise.

Without a solid BASE, and a DRIVER LAYER, you won’t have a successful project to push a UI of anything

I'm not sure what you mean by "solid BASE". Do you want to rewrite all of the existing software that implements the "desktop Linux" userspace? Who would be doing this and why, when existing stuff mostly works?

"DRIVER LAYER" in the FOSS world is just Linux. Drivers can live in the Linux tree or as small patches on top of it, with common open interfaces allowing compatibility between software and hardware. Just like they have been doing on the desktop for the past 30 years. The problem is plain: there are no open-source drivers or documentation for most phone hardware. Vendors don't have this issue because they have access to private documentation and the sources of proprietary drivers. Writing FOSS drivers requires reverse-engineering the proprietary drivers, which is very resource-intensive. The proprietary drivers that are there lock you into a particular Linux version (usually a very particular Linux version, and there's no way to solve this with any driver layer, at least without sacrificing performance and resource usage) and sometimes have proprietary interfaces with the userspace as well, which aren't easy to write a compat layer for (if that's what you're proposing). And in any case, if you are fine with proprietary stuff running in EL1, why not just run Android?

All this is completely orthogonal to making a DE on top of open standards, which is the point of open standards. For hardware that works with (mostly) mainline Linux, desktop userspace with plasma-mobile/phosh on top work well enough already. For hardware that doesn't, adding support is a lot of work, not because of any issues with the DE or userspace, but because hardware manufacturers don't publish the driver sources.