I have a 15 inch 2018 i9 MBP that's objectively a terrible device (throttling/keyboard).
With corona and WFH I'm weighing my options - right now everything is out of stock but early next year I'd be interested in building a desktop. My problem is the M1 is so good that if they do a 8 performance cores version for 16 inch MBP in spring there would literally be no point in having a desktop - I could have a single device that outperforms the desktop machine. Frankly I don't see why they couldn't offer a 13 inch varian with more cores - thermals are not a constraint.