I have had my note 20 5g for 2 months and I had to replace the stylus bc it fell out. The second stylus also fell out. I believe this is a defect with this phone.
Every time a new note releases, a few people start to claim that the note is defective because the s pen falls out. Here is what I think happened:
@BT404 The first time your s-pen fell out it was because it got bumped, causing the "eraser" end to eject, then it got caught on something and fell out. You then replaced the s pen with a third party one that has been shown to not be as exacting on its size, so it fell out because of a manufacturing defect from said third party. Only buy s pens from Samsung, not from Amazon, unless the seller actually IS amazon, and it says official Samsung replacement. You can turn on the notification that TimmA64 is referring to via:
Settings | Advanced features | S Pen | Pen proximity alert
turn this ON
@TimmA64 when you dropped your phone, you likely damaged the s pen garage, now one of the clips does not hold it in place properly. Take your phone to a uBreakIfixIt location to get the device looked at, and possibly repaired.
I have had my Note20 Ultra 5G since 8/18/2020, and have yet to have the s pen fall out, so I do not believe it is a manufacturing defect.