Try a Mi Band. I usually don’t recommend Xiaomi products because of their heavy tracking and intrusiveness, but if you only use the band during sleep, you should be fine. If you already have the know-how (which I suspect you do), you can control it yourself through Bluetooth, and the band will erase all data it holds once transmitted.
Interestingly, I became a morning person after a couple of years of being gently woken up by my cats around 7am, not with loud meowing. Now, I just enjoy waking up at that time every day, even on weekends.