I'm pretty sure it's bad for that. I have a Nexus that does not hold a charge well anymore because it is dead for so long.
As for me, I charge to 85%, but I also keep my phones a little longer than 2 years. My current phone is the 5a (late purchase), the 3, and the original. When I start noticing a difference in battery longevity is when I start shopping for a new phone.
I'm currently using a pixel 3XL, and before that an original pixel. I still use my original pixel to sync my Fitbit with, and the battery has definitely lost some life, but it would still get me through a day if I had to use it. I picked up my pixel 3XL brand new, but over 2 years old. When I took it out of the box to set it up and put it on the charger, it had 0% battery charge. I thought uh oh.. I'd never seen a new phone with zero battery charge, but I'd also never opened a 2+ year old brand new phone before
It charged up and has been working perfectly though.. battery doesn't seem to be hurt at all.
I suspect that brand new batteries that have never been put into use can better take sitting dead longer than used batteries. I have a brand new spare Fitbit Surge that I picked up cheap on clearance, that I think's a little over 10 years old, possibly more. I'm going to be setting it up in the coming days, I'm thinking the battery should be okay... what's your guys predictions? It should be an interesting experiment. Then I'll move on to my Daydream headset which was a free promo gift that I've never opened, it's probably about the same age as the Fitbit... I would be surprised if it doesn't work just fine, but you never know