I use Akeeba Backup Pro to backup several Joomla 3.10 and 4.1 sites as well as a couple of WordPress sites - all archives are post-processed to storage on OneDrive.
I have recently installed the Forms script, MachForm (https://www.machform.com) in a forms.domain.com subdomain of a Joomla 3.10 site, which is already backed up using Akeeba Backup Pro.
I would lime to know if it is viable to backup the script's directory and its separate database and post process to OneDrive.
Incidentally I schedule the Joomla! and wordPress backups using mySites.guru. I have not seen Solo mentioned on that site so assume that the scheduling will not be via that product.
I would be grateful for you thoughts and advice on this scenario.