Would you be willing to consider moving from Installatron to Softaculous? Softaculous seems to be more actively maintained, offers more scripts, and is perhaps more user-friendly too.
Installatron does not yet support Nextcloud, more than a year after Softaculous started offering it.
Tim Owens suggested in another thread that Softaculous had been discussed internally. It would be confusing for some users, I suppose, but I think it would be worth it in the long run.