No experience with Fastbreaks but I skate only high tops. Mostly for peace of mind. The higher collar/shaft does protect some but it's not like it's a structured insert or brace under the fabric that could repel an ankle roll. It's most often just thin foam, if any. Then the material warms and becomes flimsy. Depending on the shoe but at that point I'd wager most would just fold upon impact.
That's what happened after a few ankle rolls in 2023 with the NB#440h (V1). I actually kept skating the shoe when I came back. Then I went to the V2s. It happened trying tricks I rarely ever do. One on flat ground, another on an incline. Very low level sprains if they even rose to that but it was enough to nag me to try PT this summer.
The biggest you can do is rehab correctly and when it's ready, consistently strength train the area (and your entire body, imo) so you become more durable and increase range of motion. Working on deceleration and sudden stops, balance, single leg, foam rolling, stretch. Whole nine yards.