I would suggest following update schedule:
1. WWDC announcement of m2 chip is inevitable (to make sure developers are able to utilize its power). After all, it is a main place to make preparations for incoming architecture on software side. These are newer A chip and newer M chips.
2. Apple already announced that it is completely moving to ARM within 2 years, which leaves us with MacPro to be announced. Notice that Apple started M1 transition from the slowest (in multicore benchmark) devices- Mac Mini and etc and only at later stages announcing more powerful chips. The importance of this sequencing is very high.
3. If Apple announces it with M1 variant in fall, it will take another two years to move to m2, which unfeasible in current competitive market and Intel and AMD both adopting more aggressive strategies (and don't forget Nvidia), meaning that Apple will be behind Intel, which already introduced 12 gen chips. By time Apple makes M2 computer, Intel will be already on 13th or 14th gen, potentially leaving Apple in dust (in single core benchmarks). Which Apple can't allow to happen because it just left Intel.
Therefore,
on WWDC Apple has to announce M2.
M2 is an ultimate Apple's answer to Intel and AMD.
Its single core results may probably exceed Alder Lake.
So this is will be fast and powerful M2.
Developers are suggested to tweak their software for the new architecture.
Since in terms of devices Mac Pro is not yet announced, it leaves with only one possibility:
Mac Pro will be announced with M2 chip in June 2022.
In fall 2022, Mac mini, MBA and other entry devices are announced, probably using some sort of rebranded and slightly overclocked and tweaked M1 (if it is possible), actually sort of M1x, but that doesn't matter. This doesn't involve mainboard remake, which lowers costs.
Remaning Pro machines are to be announced with M2 chip in first half of 2023. This line descends from Mac Pro with M2 chip and include Studio and two Macbook Pros, while continuing to offer M1 based Studio and pro notebooks.
This will create a triple offerings
1. M1 will continue to be made
2. M1X devices will apear.
3. M2 Mac pro, probably using 2019 case, is announced in June 2022.
In analogy with iPhones, by 2022 September
we will have
Original m1 devices (think iPhone Pro Max 12)
m2 devices (Mac Pro)
M1x devices (Studio and pro notebook)