Errors when updating Redactor
With update issues like this, you'll have to run composer update rather than using the CP update button. You can either SSH into your server to run composer update or update the files on your local computer and push the new files (they'll be in vendor > craftcms > redactor) to your server. Make sure you do a database backup before doing this. After doing this manual update, when you go to your Craft CP, you'll probably get a notice that Craft needs to make changes to your database, so just click ok or whatever it says.

If Composer says there's nothing to update, you'll need to edit your composer.json file. At the top of composer.json under "require" you'll see your Redactor plugin; edit the numbers to the version number you see in the Craft updates in your Control Panel, then run composer update.