Can you please add integration for TitleManager so I can have my custom tablist w/ the parties.

You can use PlaceholderAPI to add Parties info inside TitleManager:
https://github.com/AlessioDP/Parties/wiki/Plugins-Supported#deluxechat--placeholderapi

I can't get it to work, It comes up with just having the placeholder, not the party itself

Can you attach here your configuration? both Parties and TitleManager :)

And I have PlaceholderAPI as well

Configs.zip

Your config is too much old, it seems you are using 1.5.X Parties.
You should update to the latest version and let him create new config.yml and messages.yml.

PlaceholderAPI is supported from Parties 1.6+.

Thank-you so much, I'm actually making a public H4M server