It just doesn’t show you any recommendations at all - i think it depends on you also ‘deleting’ your account history in addition to turning off history tracking

it does still (in theory) enable them to track you for other outside services, possibly even for pre-roll or mid-roll advertisements, so it really depends on what your priority is

if watching on desktop with adblock on, you can get the best of both worlds - no recommendations and no ads (disclaimer: i have not yet been given the boot for using adblock, YMMV).

AFAIK - Watching on the youtube app does not allow you the benefit of adblocking, at least not in my experience.