Hi Ted,
With respect to the meters on the Lurssen Mastering Console (which I was actually playing with a bit last night to do a quick work mix of a song I'm mixing in its early stages), it's probably important to recognize they are VU meters, rather than digital peak or RMS meters, so will read differently than the meters on your DAW. In particular, they tend to be more of an average reading, but also with some sluggishness in response (so, for example, they won't get every percussive transient). I was actually reading a few articles about mixing with VU meters yesterday, after having seen some discussion of doing that in a recent Waves master class. Here is one of those:
https://www.musicianonamission.com/vu-meter/. And another:
https://sonimus.com/blog/tutorials/vu-m ... evels.html. One question mark for VU meters in a plugin is how they are calibrated -- i.e. what does 0 on the VU meter represent? I was using the Waves VU meter plugin yesterday, and they default to -18 dBFS, which I gather is pretty common, but is that what the Lurssen plugin uses? (I don't know one way or the other.)
Beyond the VU meter nature, though, and whatever understanding (or misunderstanding) I may have of that, I have to say I'm feeling like the VU meters in the Lurssen plugin may not be reading things quite right. There is a switch to toggle between reading the input signal and the output signal. While the output meter feels to me like its reading somewhere in the ballpark of what I might expect, the input meter feels like it is reading way lower than I'd expect. And, if I crank up the input drive significantly, it is easy to get distortion. My general approach with the input level on that plugin has been to go by whatever I'd normally be doing with my mix prior to that point and, generally, not touch the input drive on the plugin.
I'm generally not looking for master wave forms that look like square waves, at least for the types of music I'm typically making. Beyond just sound and perceived loudness considerations, I'm typically targeting a certain amount of dynamic range (nominally about 14 dB, but, more realistically in terms of my results, more like 11 dB and ranging anywhere from 9 dB to 14 dB, depending on the song). The biggest reason I don't use the Lurssen plugin more is because it often seems to result in less dynamic range than I prefer, whereas I can more easily get that more to my liking with other plugins. (Interestingly enough, in the work mix I did last night, Lurssen got it exactly in the ballpark, so I may end up using it on my current remix if that still holds true after I deal with other parts of the mix.)
With respect to iZotope and learning curve, there can definitely be a steep learning curve there (and they provide lots of educational videos to help on that front). However, they also have "assistants" in a number of their key plugins (Ozone, Neutron, and Nectar) that can, at least in theory, get you in the ballpark quickly, after which you can tweak from there. I've never had any real luck with Ozone's mastering assistant -- I've done better with some of Ozone's presets (they provide quite a few, but there were one or two of those that I ended up using on quite a few of the tracks on one album I did about 4 years ago, and maybe a few of the tracks from my most recent album, though I mostly use the Waves AR TG Mastering on that one). I've only had mixed results with Neutron's assistants. There was one track I did a bunch of years back where I decided to start out by running all the tracks through the assistant to see what that got me as a starting point, not expecting much, and especially expecting I'd end up replacing the vocal processing. I was pleasantly surprised to find that it really did a good job with that track, and I don't think I even changed the lead vocal processing on what it covered, but that was definitely an isolated case for me -- I've never managed to get similarly acceptable results in further experiments with that -- and a fairly unique track among my recordings (e.g. no keyboard sounds at all).
I've also got NI KOMPLETE, also, though not Ultimate. I think there's more in that than anyone could possibly ever learn in any depth.

There are definitely some of the components I haven't even tried, as well as others I've poked around a bit with but just don't use in practice. But there are also lots of pieces I do use, some quite a bit, especially KONTAKT (e.g. I use that for pianos a fair portion of the time, and I also use Session Guitarist products quite a bit, though not all of those were in KOMPLETE, and also some third party KONTAKT libraries), some of the synths (e.g. MassiveX, Absynth, FM7), and Guitar Rig. It's probably fair to say that at least one NI product appears on the vast majority of my recordings. Then again, that would also be true of Toontrack (Superior Drummer 3), Spectrasonics (Trilian), and, to a slightly lesser degree, Arturia (V Collection) on the virtual instruments front, and Waves and PSP Audioware on the audio plugins front.
It's probably lucky I'm not a guitar player, so I have no temptation to build a guitar collection, other than virtual (and I've got a whole bunch of those).
Rick