I bought a new MacBook Pro a couple of months ago, just before the ARM announcement even though it was rumoured. Like others have mentioned, I’m not too keen on buying the first gen of the ARM laptops. If they or the second gem are that appealing, the resale value of the one I bought should still be ok.

The only worry is, if you plan to keep it for a long time, how long will macOS support the Intel line. I know Apple said they would, but iirc the PPC —> Intel change caused the PPC macs to stop being supported after 2 years.