First ... it would help to know where/with whom you host and if the hosting package leased is a shared package or a VPS (virtual private system). Many good hosting providers have a forum or even docs for customers ... or even better yet, tutorials for software applications ... like Moodle.
The softaculous issue should probably be pointed to hosting providers helpdesk ... after all, softaculous, a commercial product which isn't open source, was provided by your provider to install the moodle and from what you have desribed, it didn't work.
The second (manual install) ... unable to enter a password for admin user ... is kinda a moodle issue but maybe not 100%.
Did you wipe out the broken 'softaculous' install? The code and maybe a hidden moodledata directory inside the code that you didn't know about?
OR ... did you attempt to put manually acquired moodle code over the top of the softaculous code?
And it would be for your benefit (maybe better suggestions) if you could share what tools you have from hosting provider ... have cPanel? have phpMyAdmin? hopefully, you might have an 'Terminal" icon in cPanel or other panel for server config.
'SoS', Ken