Go to On-device site data in Chrome settings. Settings - Privacy + Security - Site Settings - Additional Content Settings - On-device site data
Leave the top setting as 'Allow'. Under 'Not allowed to save data on your device', add the following:
youtube.com
*.youtube.com
Under 'Allowed to save data on your device', add accounts.youtube.com - this fixes issues with Google login.
This will prevent you from seeing recommendations or logging into a managed account, but will allow you to search and watch videos without an alternate device or personal account.
If you have an alternate account, simply navigate to https://youtube.com/?authuser=1 where that number, 1, is the placement of any non-managed (parental controls are fine) account with YouTube access in the list of your Gmail accounts, minus one. It's usually just 1.
Then, optionally, change the currently signed-in account to another personal account or to any channel. This is only sometimes necessary, and fixes issues that start after a restart.