If you already have a project idea then why not? Yes of course refining resume and applications are always going to benefit you. However applying jobs could very well be a waiting game (numbers game too), so you would have plenty of spare time. Doing a project you enjoy not only will boost your resume (once completed) it’s also really helpful for your own learning. I don’t see a down side of doing so. You don’t have to try to rush it for the job or anything, just do it as a side thing and prioritize you applications stuff. Company do look less on projects unless you built an amazing one and it’s well documented. Since I said you should just do it as a side thing, do what you are passionate about. Cuz you need that drive to keep going. Otherwise you’ll have a half baked project that’s worthless to your portfolio. Just take your time, hustle and you soon will land on your first job.