vagfilm
porco_rosso
Regarding the piano, the Roland HP704 is a smart decision, and one that I have also been contemplating for a long time. However I am more inclined to the FP90X, but will wait for the successor of the Yamaha P515, and decide between the two (or Roland HP804...)
Regarding the VST, if classical is your main point, I would go with either the Garritan CFX (the Lite version is discontinued, but buy the full version from an american vendor such as sweetwater - cheaper than buying in europe in euros - cost 140 euros), or with the VSL Bosendorfer 280VC standard for 215 euros (only until the 30th november). These are probably safer bets than the Bluethner or the D274... You will need to buy a "vienna key" until the new iLok system is launched, but I think that the price of the vienna key will be given back on your next purchase (devious guys at VSL...)
Regarding computer, David B is the expert on Macs and VSL, but I think that you don't even need an M1 mac mini...