Google tagmanager / ads implementation for correct conversions

Hi,

I read some topics on the forum already about installing the tags and i have 1 working on the checkout page but of course without any specific triggers it will say there is a conversion every time a customer comes on the checkout page.
For better and more specific conversion, most importantly an actual sale i was reading how to do it but it seems a task for a developer.
When i ask my developer or the writer of these articles:
googletagmanagersolution.com/joomla-goog...-google-tag-manager/
googletagmanagersolution.com/google-dyna...-google-tag-manager/
They say it's a 300+usd task.

Is this actually implemented into the latest hikashop updates so i can easily find out how to do it and do it myself?
Is there something i could tell the developer so it will become cheaper for them to implement?
If no, is there a specific reason why hikashop is not easily functioning with google ads products, or do you recommend using something else than tagmanager for google ads to keep track of conversions?

Thanks in advance, Nico