Plugins Autoupdate

Hi,

I am the owner of the blog:
www.code4projects.net

and I would like to auto-update my plugins (it's boring to do it manually every time).
Starting from WordPress 5.5 there is a link near each plugin that if you click you can activate the auto-update. My problem is that this link doesn't appear.
I suspect there is this setting in wp-config.php

define(‘AUTOMATIC_UPDATER_DISABLED’, true);

My question is: how do I access wp-config.php? I don't have an AlterSite and it seems I cannot convert my website to it.

I'm sorry but you can't modify the wp-config.php code.

Bye!

Ok thank you