I'm currently running Ubuntu and it found the NAS immediately, without me doing anything. I need to reconsider my approach/options here. The main reason I wanted to use Windows File Explorer to access files/folders on my NAS was, ironically, because I had previously found it easier than using the (to me) confusing QNAP NAS operating system/user interface. Guess I'm just not cut out to be a computer user.
Your frustration and angst is understood here. All the blame does not belong to MS here for the situation however, but that is a topic for another time.

Ubuntu finding your NAS is simply because the network discovery method used by Ubuntu, or anything Linux based for that matter (including your QNAP NAS) is different than that of MS. For all of this to work seamlessly again like it did in the past will require that a method of device discovery becomes standard in the industry which at this point is not the case unfortunately. So for now and the foreseeable future the user is left to deal with this issue using any number of workarounds to do so.