Usenapp is absolutely not being discontinued.
Apple has been showing these notifications since macOS 26.4 to flag apps that haven’t transitioned to their latest distribution standards before they phase out older compatibility layers.
While the current version already runs without Rosetta, the next versions will be split into two dedicated native builds (one for Intel and one for Silicon). These upcoming versions will satisfy Apple’s new requirements and clear those system notifications.
No need to look for an alternative.
Updates are on the way!