I think April would be too soon for M3. I'd guess no earlier than WWDC 2023.Apple's strategy seems to be let each product line get some time to shine in addition to the supply chain issues. Each generation of the Silicon seems to be lets preview it first on the entry level models first. MacBook Air and entry level MacBook Pro were the first to get M1. MacBook Air was the first to get M2. Considering the iMac is getting long in the tooth with M1, it would suggest they are going to either update it soon along side the MacBook Pro 14 and 16 in the 'coming months' or let those shine a little bit and let the next iMac be the first to preview M3 by April.