Keep in mind that sponsorship is zero about you (or your racer). Also the amount racing costs you is irrelevant to a sponsor/marketing partner. All that matters is how much value you can deliver
Ideally you will position yourself (your racer) as a personal brand with an audience of followers which adds to the value you plan delivering.
Be selective about the brands you work with and how you position yourself in that regard. The shotgun approach doesn’t seem to do so well these days. Look for opportunities where your audience and potential sponsors line up, double down your efforts on those rather than chasing every/any opportunity.
Kristin Schwartzlander from Dirtymouth Communications has a lot of insights on this subject: https://www.kartpulse.com/article/184/sponsorship-pricing-it-s-too-expensive-versus-it-s-not-worth-it
You need an online presence for sure, but setting up your own website, then driving traffic to it is probably more trouble that it’s worth for you at this point. My suggestion would be to leverage major social media for now as a starting point and focus on making connections/networking with folks.