Spreadsheets used to be the way it was done, until Carta came along. So, sure, it's possible. I suspect that if/when you raise from professional investors, they're going to want you to pick a SaaS solution. Probably also a good idea if you plan to hire. If I'm taking a job, I don't want my employer cheaping out on managing my equity.
(I am not an expert. I have been a founder, but my startup did not make it far enough to have this concern. I have also been on the leadership team of a company, but equity management was outside my concern.)
(I am not an expert. I have been a founder, but my startup did not make it far enough to have this concern. I have also been on the leadership team of a company, but equity management was outside my concern.)