SEO (Search Engine Optimisation) is a long-term game. It’s also relatively simple to execute once you have structure. A majority of my clients have come to me with existing websites, my job was to make it into an SEO friendly website. I do that by simplifying and structuring their sites, removing anything that impedes the end user and doesn’t add to their message.
Yes, you most likely need a website. No, it doesn’t have to be very fancy. Most of the time, only you care about the fancy features, the end user cares about ease of use, speed and most importantly, whether you have what they’re looking for. Google serves the user.