Font scaling across devices.

Audio and Graphics
#1

main.lua

local textoptions = 
{
    text = "text",     
    x = display.contentWidth * 0.5, 
    y = display.contentHeight * 0.5, 
    width = display.contentWidth - 150,
    font = "fontfile.ttf",   
    fontSize = nil, --makes it to system's default font size
    align = "center" 
}
 
local myText = display.newText( textoptions )
myText:setFillColor( 255, 0, 0 )

config-

application =
{
    content =
    {
        width = 320,
        height = 480,
        scale = "letterbox",
    }
}

build.setting is default.

The text is fine on phones and iPhones (though it is smaller than wanted), but when you go to iPads and other screens, it is barely legible and smaller than on phones. I don’t want to set a specific fontSize, as the looks will vary from device device. I thought nativesystemfont would be okay for every device, but unfortunately, it doesn’t work.
Is there some way to fix this?
I am testing on a Windows 10 PC.
Thank You.