Crossing Bismarck's T brings destroyers into the battle

What changes if Norfolk and Suffolk maintain contact and Holland crosses Bismarck's T?

The geometry helps, but the decisive addition may be a coordinated destroyer attack that forces Bismarck to answer several threats at once.

Crossing the T alone would not guarantee a different result. The more important change is that Holland's destroyers may remain with the battle force instead of falling behind. Bismarck would then have to engage Hood and Prince of Wales while cruisers operated at range and destroyers rushed in with guns and torpedoes. Multiple simultaneous threats overload attention and fire control, increasing the chance that one British attack gets through.