I also feel when you do break your focus like that, the quality or the content is not going to be as good or what's expected. Like the 2nd update to Radiant didn't feel as strong as it was as the first release. I think it because they kind of hurry up some ideas and threw it together at the last month or 2 and called it an update.
It can help sometimes to have something different to take your mind off things, even if they seem related. I studied something called "Business Mathematics", consisting of - not surprisingly - business and mathematics. And even if they seem similar from the outside, they really are not and require different "skill sets". And when my "business skill" was tired, I actually could do maths as a "refreshment" and vice versa - it was still work, don't get me wrong, but it was way less exhausting and I had way more ideas on how to move forward. So if you feel constricted by some story lines in one game, not having the same (although other) constrictions in a different game can mean you feel more free to go on, even if you are not. When making graphics, you can get tired of the same old stuff, some other may help.
The flip side you mentioned is true, of course, you can lose focus, forget where you were, need time again to get "into the groove" after some absence. I just wanted to say that it is not all bad working on two projects at the same time.
That being said, I also don't think it is the best idea to have both projects "on demand" on Patreon at the same time. It does invite questions about how much you are into each of them. It might have been a wiser move to keep this one as a side project for now, and when the others are (almost) finished, you have a nice headstart.
