See #38177 (comment) :

this should indeed be a pool based on cache.app rather than using cache.app directly, to avoid key conflicts (keys must be unique inside the pool, so sharing the same pool between multiple places is a bad idea as they need to cooperate on their naming of keys)
see

symfony/src/Symfony/Bundle/FrameworkBundle/Resources/config/cache.php

Lines 68 to 71 in f06f2f0

	->set('cache.messenger.restart_workers_signal')
	->parent('cache.app')
	->private()
	->tag('cache.pool')

for the service definition of an existing one

In the rate limiter config, we're also using cache.app directly. This should be changed to using a custom cache pool: