I also feel like I'm in a similar boat on finding a partner for motivation. Always found it easier to work on projects with friends back in HS/College and now it's a lot harder to stay on track/motivated. I think part of it is bouncing ideas back and forth and kind of hyping each other up.
I've used https://www.focusmate.com/ before, might help you. Not exactly the same but sometimes I find just having someone else on a video call with you is a motivational push.