After a day of working with Flarum, I can confirm that this has fixed the problem for me. I just wanted to say for anyone out there also having this issue that if you don't see "etc/apache2/apache2.conf" anywhere, you can just create it. Then paste this in apache2.conf:
<Directory /your/path/to/flarum>
Options Indexes FollowSymLinks
AllowOverride All
Require all granted
</Directory>
Refresh your install page from Flarum and it should work now. If not, you can post something down below and I'm sure the administrators on this website will help you with your problem.
Edit 1: I also made sure to give the flarum folder 755 permission as well as index.php
~Dayornight