I went through this exact situation about 18 months ago and wanted to share what I learned. Our angel investor put in $150K on a SAFE and then started pushing for a board seat before the note even converted. We initially resisted because we felt it would give one small investor outsized control, but we eventually found a compromise that worked for everyone.
Instead of a formal board seat, we offered a board observer seat. This means the investor can attend board meetings, receive all board materials, and participate in discussions, but has no voting rights. This gave them the transparency and involvement they wanted without giving them governance authority over the company. We documented this in a Board Observer Agreement that our attorney drafted.
The key provisions we included were confidentiality obligations, a clear statement that observer status does not create fiduciary duties, and the right for the board to exclude the observer from discussions involving conflicts of interest. We also included a sunset clause that converts the observer seat into a discussion about a real board seat at the Series A, when governance would be restructured anyway.
If your angel is insisting on a voting board seat for a relatively small investment, that is a yellow flag. Most experienced angels know that board seats at the seed stage are typically reserved for lead investors putting in $500K or more, or for institutional investors. A $50K to $200K angel asking for a voting seat may be signaling that they intend to be a difficult investor to work with going forward.