Unfinity, the latest Un-set, was set to release on April 1, 2022 (see "'Magic: The Gathering' 'D&D' and 'Masters' Sets"). The supply chain problems were specific to the Unfinity product line, thus WotC opted to push the set's release off till the second half of 2022. Additionally, Unfinity promos will no longer ship with retailers' Kamigawa: Neon Dynasty marketing kits, and will be sent out closer to Unfinity's actual release date.
For more information on future releases of Magic products, check out ICv2's 2022 calendar (see "‘Magic: The Gathering’ Release Calendar For 2022/2023").