Hi,
So on the views "checkout / cart" you can replace the occurrences of:
$this->currencyHelper->getRounding($this->full_total->prices[0]->price_currency_id)
By:
round($this->currencyHelper->getRounding($this->full_total->prices[0]->price_currency_id),2)
And in the view "checkout / listing_price" and "product / listing_price" add too this php round() function on the desired elements. It require some PHP knowledges.
The round needs to be added around the occurrences of:
$this->currencyHelper->format(...)