Change the side bottons

Hi Patrick,

It's always possible the buttons are just gummed up so it's worth your while to try cleaning them first before you go digging into the phone replacing parts. Get some 90% or higher concentration isopropyl (rubbing) alcohol and a toothbrush and clean the button as best you can. Give them some time to dry (it won' take long) and see if that's made any difference.

If you've done everything possible and they just refuse to cooperate, then it could indeed be a problem with the switches, and the only real fix for that is to replace them. The three side buttons for volume and power are all integrated into a single flex cable, so you'll be replacing all three at once. Here's an example on Amazon of the part you'll need; you can check eBay and AliExpress for other options if you want.

Amazon.com: MEEFIX Power Volume Button Key Flex Cable Replacement Kit for Samsung Galaxy Note 10 Plus : Cell Phones & Accessories

Sorry to say, iFixit doesn't have a guide to show you how to do that job, but there's a French site called SOSav that does. If you use it with a browser like Chrome that has a translator built in, you get a quite usable set of instructions on how to replace your side buttons.

Réparation Nappe power, volume et bixby Galaxy Note 10+ - Guide gratuit - SOSav.fr

You'll want to check the operation of the mechanical part of the buttons once you get the switches out to make sure the three buttons all move freely. Once the new flex is in place, verify that all three give you satisfactory clicks before buttoning the phone back up.

Good luck; let us know how it goes!