Yes those super high ones are usually freeze concentrated (partially frozen, then ice is removed which removes water, what is left is stronger) multiple times to reach such high ABVs.
The highest you will see actually fermented is usually around 18-20%, but there are specialty yeasts that can get up to 25%. Then you can get even higher with extended aging in spirit barrels where some ABV is picked up by absorbing residual spirit as well as evaporation increasing the strength. Sam Adams Utopias for example comes in at 28%
Worth mentioning, freezing and skimming ice is a clever distillation process. It’s also illegal under any other circumstances that distillation would be illegal, but nobody much cares.
It’s pretty easy to get into the ~15% range with the right yeast (champagne yeast is the best starting point) and attention to sugar conversion (I wish I could remember the details here but I haven’t brewed for about a decade) and importantly for beer, good ventilation. I had a barleywine that should have been in this range ferment for about 12 hours and it clogged the airlock, exploded the carboy, and generally ruined everyone’s day. But not the way it was supposed to ruin anyone’s day.
It's not so much a problem of the yeast and attenuation. Nottingham should be fine up to 14% and for a high gravity beer somewhere above 75% attenuation.
The issue is yield and lautering. The mash is so thick, or rather there's so much of it, that proceses need to be adjusted to account for that, and from experience yields are much lower in a typical entry level craft brewing system (400L).
The highest you will see actually fermented is usually around 18-20%, but there are specialty yeasts that can get up to 25%. Then you can get even higher with extended aging in spirit barrels where some ABV is picked up by absorbing residual spirit as well as evaporation increasing the strength. Sam Adams Utopias for example comes in at 28%