It's not just your relay. It's a thing. Have a good look at the stats. Nostr adoption, engagement, and retention are all quite low and have declined significantly from the major adoption spikes. The users that joined after X was banned in Brazil and other events before that like the Reddit and TikTok spikes over mostly did not stay or regularly engage. There are only ~36,000 weekly active users on Nostr right now, and less than 15,000 daily active users.

https://stats.nostr.band/