I appear to be blind as I can't seem to find a way to alter the initiative so it's not only affected by dex. 

There is no specific spot for that. In the combat tracker it doesn’t even include Dex for Monsters, it literally just rolls randomly for all monsters. What I do for Monsters with specific Dex boosts is to use the same system of “rollables” that they use for Monster attacks, just under “special traits” instead. That will put an individual button in that Monster’s statblock and the you can roll that monster special and manually enter it’s specific initiative.

Here’s one with a fixed number (+5) you can use and adjust as needed:

[ rollable]Initiative;{"diceNotation":"1d20+5","rollType":"roll","rollAction":"Initiative"}[/rollable ]

Here’s one with an additional die (+1d4) added that you can use and adjust as needed:

[ rollable]Initiative;{"diceNotation":"1d20+1d4","rollType":"roll","rollAction":"Initiative"}[/rollable ]

You can also combine them:

[ rollable]Initiative;{"diceNotation":"1d20+1d4+5","rollType":"roll","rollAction":"Initiative"}[/rollable ]

I hope that helps.

This works, I can see it in the stat block and I'm able to click on it, but It only rolls it. It doesn't add the result to the combat tracker. Is there a way that the monster get added to the tracker after rolling this?

Also adding the monster first to the tracker and then rolling the Initiative, doesn't change the value in the tracker.

No, only the actual Initiative result gets automatically fed to the tracker, you’re gonna hafta manually enter the results.

*tears* yeah I guess I will have to do that Thanks.