How much do you trust preflop ranges and when to get out of theory?
Follow them by default. You should deviate either if you have a good strong read on your opponent, mainly judging by their river cards and by their frequency stats. If not - just play GTO until you have a good enough read on them, as in this case you will just be generally unexploitable to other opponents.
Mind the bet sizes. If your opponent opens big for no reason - call and 3bet tighter.
Though you should deviate by default if you are at a weak table with calling stations, where mass-calling and mass-limping is a regular occurence. Standard preflop ranges just won't work there (you'll still be technically unexploitable but unexploitable play will be unprofitable and honestly unnecessary there). You'll have to have an over-openlimping range (generally suited aces, small-medium pocket pairs and with caution suited connectors with suited gappers) and a huge open range (mainly
hands that play well heads-up but poorly multiway, size depends on how rigid your table is (you need a big enough sizing to prevent multiple callers), while the ranges themselves depend on the sizing: as the necessary size gets bigger, you have to open tighter)