Ok.

How to be more productive and less distracted:

I can only talk about myself. Of course. The problem here lies already in the word productive. I know producer is a common word but i honestly believe is that real music is not produced. But given to you. Lets call it from the deeper self. And the only thing you can do is to be open wide enough to recognize it when its there and then translate it. Being in tune. And the brings me to answer your question.
The main point is the question "where am i". I am inside myself. In my brain? In my heart? Connected to my feelings? Outside of myself? Focussed where to? When i am connected very good to my feelings then making music is actually VERY easy. Simply start the computer. Choose one sound which sounds promising in that moment and start playing. In my case MAKE music, .ACTUAL playing music leads to finished songs. But its always about the process of making music. Never about finishing. Being connected how stuff FEELS is core for me. On the other side when i am less centered on myself, more in the brain or dizzy its easy to start netflix and let myself get flooded with films which do close myself down even more. The goal is to be with my music. Spend time in it. Playing and maybe arranging later when i found something, but this is playing, too.
Being fully aware that its not human to be there the whole day. Sometime distraction is necessary or fine, too. Balance is key and how to get into that centered and well connected state? I would say the best tip to get grounded is to clean up the Appartment ))) or sometimes to eat a bit. Or have a walk or sit under a tree. Whatching youtube.... Nope. Better have ONE good song in a live time than 20 blabla albums. But 20 albums is fun, too. Dont judge yourself.

I can relate to what you say. Playing music is the way I am able to come up with tunes. I usually do try to strive for completeness when I come up with something that I like simply to be able to say I have "finished" this song and can start sth new with a sense of closure. Otherwise the melody of the unfinished thing will stay in my head to haunt me. So I try to find a Verse Chorus Verse Chorus Chorus end type of structure in what I play then I take it to the next rehearsal with the band and ask them for feedback and that's when the songwriting starts for real and that's the part that takes ages. Which sometimes is frustrating for me bc I really dislike perfectionism. I feel like rolling with it. I'm a fan of letting go when it comes to writing material. Just finish up, put it out, you can always revisit it later and free up your mind for new ideas.