While I hope it works out for you - I'm wondering what makes you think it's just about lack of motivation?
"Finding motivation" from finding the joy in things is what I hope to recover. Also starting new habits and not tying so much of myself to my work/current company is something I have to learn better to do and is a goal of mine during my break.
When you care deeply about the area you are working in, it is hard to turn off. This combined with a very ambitious company lead me to crash and burn about 18 months ago. Tried to recover with short breaks and while that helped, it kept going back to the same pace and have decided if I want to kick this exhaustion, I need a longer break to form better habits and try to find that joy in what I do again.
Whether or not I'll be successful, I don't know, but need to try.
Exactly that combination of "you care deeply about the area you are working in" and "hard to turn off" (even with less of "very ambitious company") - will eventually bring you back to the same situation, unless you change habits/approach/etc.
Instead of focusing/pushing for "not tying so much of myself to my work/current company" and "motivation" - perhaps it's better to focus on training yourself when and "how to turn off" and not slowly drift towards old habits?
And I think I know what you mean by "depression hits pretty hard and you stop doing things for yourself due to lack of joy/seeing the point in doing anything". Though in my case I realized that it originally started from myself feeling guilt where I was nagging to myself how I can't do whatever fun thing while there was some other work thing/project where I thought I'm behind.
So slowly over time that guilt made fun things less fun, and combined with stress started to skew perception of how productive I am, and how long something will/should take ...etc. Eventually that skewed perception spilled from work to personal life - so for those things/projects that were still at least somewhat fun/enjoyable I also started to be annoyed by them taking longer than what I thought they should take.
I've talked about it some in the past, re: MKP and other men's support groups along those lines (or just a solid group of friends). Much of it is just recognizing the emotion(s) and putting myself into a place where I can express/vent it properly.
Along those lines actually, has anyone else noticed a boost/burst of energy/productivity/etc after the elections last week? I think thats a malaise that hasnt really been talked about much (yet).