Howard Miller

You can upgrade from 4.2.3 to 4.5 directly. Read the 4.5 release notes - https://moodledev.io/general/releases/4.5

If you want to transfer the site to a new server then there's nothing to stop you transferring the database and the 'moodledata' files and then upgrading them to 4.5. There's no need to get the 4.2.3 version running.

The only reason to get a new version of 4.5 installed would be to confirm that it will run at all on your new server. That's not an entirely ridiculous thing to do.

PHP 7.4 has been end-of-life / unsupported for over two years and the more recent versions of Moodle won't run on it. So that's not a good start

I'm not sure how likely you are to encounter Workplace devs here. However, you never know...

Is this Moodle Workplace?

(Standard) Moodle doesn't have those things.

Yeh - we call it the "10am effect". For some reason, 10am is peak login time and we've had some issues over the years.