An easy thing you can do is set the text size of your labels to be half of the absolute Y size of the frame. You can do this everytime the frame size updates.
local textLabel = script.Parent
local function updateTextSize()
textLabel.TextSize = textLabel.AbsoluteSize.Y / 2
end
updateTextSize()
-- This is so we only update when the text label size changes, which means we're not performing more calculations than we need to
textLabel:GetPropertyChangedSignal("AbsoluteSize"):Connect(updateTextSize)