I want appointment reminders from Google Calendar appointments, hopefully allowing different sounds for different calendars, but for sure playing the sound whenever the Google Calendar reminder is set for, and until dismissed. But my phone isn't glued to me, nor am I to it. I might or might not have it with me outside. I don't hear it in the shower. I don't rush back to it to see if I missed something. One little ding doesn't do it for me.
My Galaxy S5 worked for me. I had CalenGoo set to repeat reminders every 5 minutes.
My Pixel 3 XL doesn't. CalenGoo is set up just the same, but Android 12 only occasionally plays the sound. Might play it hours late, or not at all, even with the battery saver turned off. One issue apparently is if I haven't opened an app for N days, the notifications just stop. It's an issue for me for both CalenGoo and WhatsApp. I usually use the computer, not the phone. But even if I remember to poke the app and keep the battery saver off, the reminders still usually just don't.
I tried 'Repeat Reminder Plus', but it presumes as soon as I open the app, it's done.
Maybe CalenGoo hasn't been updated as needed for Android 12, and if I try a slew more calendar or repeat reminder apps, I might find one that works?