Sheikh 'Abdullah Al-Iryani hafidhahullah (24.Sha'ban.1443 - 28/03/22):

“It's okay sometimes to do as the Abyssinians did in the Prophet’s masjid. As for dedicating a place in the masjid for children’s play, then this is not from the Sunnah. But if they are in need of that for the reason cited, then somewhere separate from the masjid nearby.”