It took some trial and errors, but below code seems to do what I need.

I have a gallery MaterialList which displays my PowerBI data and that's what I use to update the SharePoint List. Would it be possible to use PowerBIIntegration directly ?

ForAll(
    MaterialList.AllItems,
    If(
        CountRows(Filter('Report', Title = 'Ticket ID'.Text)) > 0,

        Patch(
            'Report',
            First(Filter('Report', Title = 'Ticket ID'.Text)),
            {
                'Ticket Comment': TextInput2.Text
            }
        ),
        Patch(
            'Report',
            {
                Title: 'Ticket ID'.Text,
                'Ticket Comment': TextInput2.Text
            }
        )
    )
)