Possibly a silly question but have you tried adjusting the vibration strength on your phone? What model are you using? Some have the ability to set different vibration patterns, which can help it to be more noticeable.
Yes, I tried max intensity keeping it inside my pants. It was still too weak. What I’m doing now is to put my phone on desk next to the keyboard so I can awkwardly pickup the phone whenever it moves. Haven’t tried the vibration patterns though. I should do that tomorrow.
If it’s on your desk, you may also want to consider checking under accessibility in your device settings. You should be able to enable the setting to make your phone’s camera flash blink for notifications.
On my S23U it’s under Settings > Accessibility > Advanced Settings > Flash Notification.
Otherwise, all I can think of is a Fitbit. It requires an app but lasts a good week on a charge. It also tracks your sleep and fitness. One of the smaller models can be neat without leaving too much into the usual smart watch type stuff.