Spoiler candidate dude, sorry. I really despise Biden and the two party system, but there’s zero choice here, it’s Biden or fascism.
The right won’t have a spoiler candidate siphoning votes in November, every state RNC is going to make damn sure of that.
Best chance to change the system is to get Biden in, then pressure a democrat-controlled govt to adopt change. Federalize first past the post, maximum age limits, limit lobbying. None of this has a chance of ever happening at all if the left cote is split and trump wins. If Biden wins, there’s at least a chance, however small.