MacTracker says there was a 2020 iMac 15 & i7...
August 2020 DiscontinuedMarch 2022 Model Identifier iMac20,1 or iMac20,2 Model Number A2115E MC3442 Order NumberMXWT2LL/A (3.1 GHz), MXWU2LL/A (3.3 GHz), MXWV2LL/A (3.8 GHz) Initial Price$1,799 (3.1 GHz), $1,999 (3.3 GHz), $2,299 (3.8 GHz)Support Status Supported ColorsSilverWeight and Dimensions19.7 lbs., 20.3" H x 25.6" W x 8" DPROCESSOR
ProcessorIntel Core i5 (10500, 10600) Core i7 (10700K) Core i9 (10910) ("Comet Lake")Processor Speed3.1, 3.3, 3.8, or 3.6 GHzMaximum Processor SpeedUp to 4.5, 4.8, or 5.0 GHzArchitecture64-bit Number of Cores6, 8, or 10Manufacturing Process14 nm Security ChipApple T2 (APL1027)Cache12 MB (Core i5) 16 MB (Core i7) 20 MB (Core i9) L3System BusIntel Direct Media Interface (DMI) at 8 GT/sBoard IDMac-CFF7D910A743CAAF (iMac20,1) Mac-AF89B6D9451A490B (iMac20,2) STORAGE AND MEDIA
Storage256, 512 GB, 1, 2, 4, or 8 TB flash storageMediaNonePERIPHERALS
PeripheralsMagic Keyboard or Magic Keyboard with Numeric Keypad, Magic Mouse 2 or Magic Trackpad 2
The last 21.5" was... March 2019 DiscontinuedA pril 2021