MacBook Air won’t connect to iMac folders since macOS 15.4 update

My MacBook Air began failing to connect (on WiFi) with my iMac folders via Finder > Network, even though it still appears in the sidebar. However, it will still Share Screen with the iMac without a problem. This failure to connect to folders occurred sometime after the previous MacBook Sequoia update (15.4.x). I thought a recent update to 15.5 would resolve the issue, but it has not. Conversely, the iMac (Ventura 13.7.6) continues to connect with the MacBook Air, both to its folders and via Share Screen. I’ve tried forgetting the WiFI network and reconnecting on both machines, restarting, etc to no avail. Any other suggestions?

[Re-Titled by Moderator]