What I've been doing recently to overcome this problem is working in smaller chunks of time. Not listening to the song on loop.
So once the song is about almost done, I do this:
1. Bounce the track to audio.
2. Listen to the track on my laptop or iPhone. I find it more beneficial to be away from the DAW while doing this, it helps to just focus on listening to the track and not get distracted by what the track looks like in my DAW.
3. Without stopping the track, I take down notes of what needs to be fixed, added or taken away. I listen to the track about 3-4 times, usually by then I will have identified all the things that needs to be worked on. If not, I'll listen some more and take down more notes.
4. Finally, I open up the song in Bitwig, set a timer for 25/30 minutes, and get to work based on the notes from before. I check off each thing as they are addressed.
This approach has kept me super focused and productive, and I finish more tracks this way. It's helped me avoid ear and mental fatigue as well because I'm working in smaller chunks of time. It's also more fun this way!

I totally understand how it can get boring after a while.