when a Buddha attained final nirvana, is he able to have his own
pureland paradise after his final nirvana?
this is one of the speculation question, that the Buddha did not
answer specifically, as it will confuse his questioner even
more.
Buddha said that even right now, there is no self of a
tathagata, so how can there be a tathagata that exists, not exists,
both exists and not exist, or neither exist nor not exist after
death. Since existence/non-existence implies a 'self' that can be
existence or non existent.
This is simply talking about the no-self doctrine. In no way
does it imply that there is no conventional self - as Buddha said,
he uses conventions like anyone else, understanding it to be only
for convenience - words like I, you, me, Buddha, are all
conventions.
Therefore it does not contradict Buddhas making pure lands. None
of the suttas mentioned anything like Buddhas cannot make pure
land.