If I have an alpha/beta version of a product, should i be working to launch it to build traction or rather apply for YC ?

Also, I have a day job which pays well and i need the job but my passion is to build innovative/useful solutions. I wonder how i could be full time at YC or is it ok to be working part time?. I have also heard that investors would not even look at your proposal if they know you're working part time on it.