FB2 liter was a 0w20 for Impreza and Crosstrek wife's 23 is 0W20.
The lubricant will flow to places it need to be, but controls and systems will balk at an overly viscous fluid and with an overboard HTHS and car will be unresponsive to a fault.
Been there and done it a few times over the past decade. If you DD a car from new, you will know if it is working well enough to design intent.
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Only go as high on HTHS as you anticipate the necessity. Script on the oil fill cap is the starting point.