The button never stops opening suited cards at any depth. What it stops opening is offsuit hands that flop dominated pairs.
Only hands that can make the nuts — or fold without regret — belong in the range. Offsuit big cards win small pots and lose enormous ones.
The button is the best seat in poker, and it appreciates with every blind of depth: absolute position on every postflop street of a potentially enormous pot.
Assumes a live-standard open to ~4bb, raise-or-fold. In straddled games, halve your effective big blinds and read the chart at that depth.