[horde] reinstall advice with data preservation needed

[Frank Lienhard]

Hello,

I have been too sloppy with updates, so I'm in the following situation:

Current install is horde 5.2.16 running with php7.4.
I use shared hosting, so the option of running php7.x will end soon.

I dumped the horde DB and made a backup of the /html/horde directory.

As I understand it, the installation way of choice would be via composer 
(not with PEAR anymore) as described here:
https://github.com/horde/horde-deployment#readme

So after backing up the db and the horde dir of my current 5.2.16 
install, can I simply delete the old horde install dir and start with 
the composer deployment?

Do I not need to set up a DB first (at least in my case on a shared 
hosting, where the db names have to follow a certain naming pattern?).

thanks