Came here to drop 5. Stayed for arrangement and lyrics. I was hoping to hear them!
I think the mix could use some revisiting to bring out the rhythm guitars on the sides more, perhaps take some verb off those kicks and toms. Essentially carving out space for bass to exist in the center channel relatively unmolested. I wonder if what could be causing some of the flat feel could be monitors or cans which don't translate that sub noise, and at the same time over accentuate highs. There's something called RealPhones I recently learned about which you can grab to effectively mix on headphones, but it's paid.
3:19 where the mix is less condensed, it sounds more ideal -- the compressor is really clamping down on the mix as a result of those thick bass frequencies. Cutting some verb wet and bringing the kick down will help. You can actually use sidechain to make sure the transient cuts through without harming too much of anything, and adjust it for each individual track so that it isn't very noticeable, then trim down the kick to a more manageable for the compressor volume.
Sorry if I'm writing a book and it seems to be all critique! Just know that I have no other negative comments about anything else. I very much enjoyed it!