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That's a different exception. You are getting

500 FOF: View \Akeeba\Backup\Admin\View\Schedule\Html not found 

This refers to the file administrator/com_akeeba/View/Schedule/Html.php which does exist in Akeeba Backup, as in: we include it in our installation ZIP file. The fact that your site cannot find this file tells me that Joomla messed up the update, removing files of the old version without replacing them with the new version. This is a bug in Joomla that affects about 3% to 5% of updates and has been around since Joomla 1.5.5. This bug has proven impossible to debug. I have experienced it myself but trying to reproduce it on the same server didn't work. It seems to be very random or requires conditions that are very rare. This makes it impossible to reproduce reliably to debug. I've been hunting down this bastard of a bug for ten years!

At least it has a fairly straightforward fix. Download the installation package for Akeeba Backup 7.4.0.1. Go to the backend of your site, Extensions, Manage, Install. Use the Upload and Install tab. Install Akeeba Backup twice in a row, without removing it before or in between. Joomla will copy the correct files and the problem will be solved.

The broken symlinks are just that: broken. They point to nothing. They needn't be there. Therefore they are not backed up. This is the expected and desired thing to do with them.

Remember that a symlink says "whenever someone tries to access file/folder A you need to instead look at file/folder B". If file/folder B no longer works the symlink is broken, i.e. it points to nothing. It is useless. If someone were to try and access it they'd just get an error. So why include it in the backup when it's very clearly bust? :)