If I had Wavelab (and I did demo it last year but ultimately decided it didn’t do enough for my workflow for the price) I would take the two-track stem of every mix and master those together. In Wavelab you can have master effects, but you can also insert effects on each clip and master them individually that way. I would say it’s not a huge downgrade to master and assemble it all at the end - that’s how I work. It is nice to see everything laid out in front of you as it will be on the album, but you can keep track of that in your head and make small adjustments to individual tracks that need it at the end.
If that’s how you’re feeling about the master, then you need to go back and fix the mix. The nice thing about mastering your own work is when you hear something like that you can go back and fix it right away. I have one client who pays me to both mix and master for them, and I refuse to start their masters until they are 100% happy with every mix - even if their only note is the hihats need to be raised by .2db, you want to fix that in the mix if you can. The ideal master is just going to raise the loudness to your LUFS target (I aim for around -14 to -9 LUFS depending on the song/album/genre) and adjust the tonal balance to get it in line with other tracks and compensate for any psycho-acoustic effects of changing the loudness. If anything is wrong with your mix, making those tonal adjustments is harder because it takes whatever was wrong with the mix and throws it even more off balance.
As far as prioritizing LUFS or dynamics, that’s up to you. I personally like more dynamic mixes/masters than the industry average, so my masters are a little quieter than average for a given genre (though still always at least -14 LUFS). Most people will choose the louder master, so you may want to sacrifice more dynamics to get louder masters. Wavelab has really good tools built in, so if you practice with them I’m sure you can get a good balance of being loud enough without giving up too much dynamics.
Once your master is done, you should not be pulling it into Audacity or anything else and boosting it. You need to have the level you want when you finish your master. If you need to turn up your mixes, do it first thing with the clip gain in Wavelab, then do all the rest of your master processing at that level.