You can switch profiles and even have different profiles active in different Chrome windows, without restarting Chrome.
https://support.google.com/chrome/answer/2364824?hl=en
(I am not saying this makes it all better, trying to use more than one Google account is a _mess_ no matter what. But that it's one workaround I discovered recently, which has been lessening the pain somewhat)
They help me to separate my work and personal everything. Not just email, but my tabs, bookmarks, saved passwords, extensions, etc.
On Firefox I click the user icon, choose my work account and my personal account loads.
On Chrome I click the user icon, choose my personal account and my work account loads.
It's so fucking frustrating. I've cleared cookies, cache and history completely and the problem just comes back later that day.