You buying the Core i9 tells me you want a no compromise experience due to work.Will see what they are priced at, but I currently do a lot of VM work on it (mostly x86 Linux, but some Windows) which I wouldn’t be able to do on AS (at least yet). That might change next year though. Also it is extremely overkill for them (i9, 40GB RAM etc).
I get that as I also got a Core i7 when the your chip was not available on the iMac yet.
But given that M1 Macbook can outperform your iMac it might be a cost saving to just buy the base model at $1800? I'm doing that come the redesign.
By 2022 I expect almost all apps to have Universal 2 binaries. Would not be surprised if Microsoft will offer Windows for ARM as a download.
Windows used to be offered on other chips including IA-32, MIPS, and DEC Alpha; support for PowerPC, Itanium, x64, and ARM.