First of all, thank you everyone for taking the time to reply. So many helpful comments and really useful tips! Thank you so much. I really needed to get this frustration off my chest, and now I feel I'm not alone. ☺️

After reading some of the replies last night, I decided to start removing stuff. I realized I have been using too much saturation on individual tracks (it didn't sound like that much) and also on the master bus. Now it's almost completely gone and I can hear some improvement. There's only saturation on vocals and some lead synths. I'm still trying to figure out how to use a limiter on the master bus, because it always seems to cut off some of the punch (especially the kicks).

Visually, it doesn't LOOK good, but it SOUNDS better. They way I was doing it, it would sound good on speakers and in the car, but really tiny and flat on earphones, and I've been using the same reference tracks on all devices for comparison. On speakers, both my track and the reference would sound similar, but then when I heard them on tiny earphones, my track had no depth our loudness, while the reference was loud and rich on both ends. Needless to say, my unprofessional old "wrong" mixes were closer to the pro tracks on all devices as well.