Re: "where did I put that" -- I got a set of Apple airtags recently and they've been a godsend. I also have an apple watch, so via the watch I can find my phone, and via the phone I can find my wallet/keys/etc... They're awesome.

Re: reminders, one thing I've noticed with any sort of reminder system based on alerts/notifications, is that while they work for a while, eventually my brain just starts ignoring the alerts. I honestly have no great solutions for that. This applies to any sort of organizational system I've tried, actually.