Actually, TSMC's N3E process is somewhat of a regression on the first-generation 3nm process, N3. However, it is simpler and more cost-efficient, and everyone seems to want to get out of that N3 process as quickly as possible. That seems to be the biggest reason Apple released the A17(M3) generation and now the M4 the way they did.
The N3 process is in the A17 Pro, the M3, M3 Pro, and M3 Max. The A17 Pro name seems to imply you won't find it trickle down on the regular iPhones next year. So we'll see that processor only this year in phones, since Apple discontinues their Pro range of phones every year; only the regular phones trickle downrange lowering their prices. The M3 devices are all Macs that needed an upgrade due to their popularity: the Macbook Pro and Macbook Air. They made three chips for them, but they did not make an M3 Ultra for the lower volume desktops. With the announcement of an M4 chip in iPads today, we can expect to see the Macbook Air and Macbook Pro upgraded to M4 soon, with the introduction of an M4 Ultra to match later. We can now expect those M3 devices to be discontinued instead of going downrange in price.
That would leave one device with an N3 process chip: the iMac. At its sale level, I wouldn't be surprised if all the M3 chips that will go into it will be made this year, with the model staying around for a year or two running on fumes.