https://psalm.dev/r/10f4d65384

Got: UndefinedPropertyFetch.
Expected: no errors when #[\AllowDynamicProperties] is specified.

PHPStan yields no errors if #[\AllowDynamicProperties] is specified:
https://phpstan.org/r/3c01def8-a910-4d64-839b-9e63e135e269
If the attribute isn't present it yields Undefined Property too (and it's fine):
https://phpstan.org/r/48b21122-ebad-4b7c-8b9b-50d7b2b7120c