White tongue

For the past few months, I have had a white coating on my tongue and I can’t seem to get rid of it. I try to brush my teeth and tongue twice a day but most of the time I’ll just do it once a day. I also rarely ever forget to floss. Is this just from inconsistently brushing twice a day or is it something else? I do have a terrible gag reflex so it’s hard to reach the back of my tongue, which is where most of the white is. But at the same time, I see white even in the areas that I can easily brush. I’ve tried different types of tongue brushes/scrapers and none of them have been effective.