Can I do CAD and rendering work on my Mac by Remote Desktop(ing) to a powerful windows machine? (wired connection)
The performance of any Remote Desktop connection by the laws of physics and the need to encode the data is always slower than a native display.

So, no, the performance can’t be as good with a remote connection adding latency and delay.

That being said - practically, you are always going to be more productive than getting up and moving to another computer and you can get prodigious amounts of work done remotely across a continent let alone across the room. With a decent WiFi connection (say 802.11 ac and less than 10 radios connected to the AP and low interference / SNR above 10 dB ) or any 100 megabit wired/switched ethernet you will have a hard time measuring the delay or worrying about performance. Gigabit ethernet is even better.

I wouldn’t worry about this performance loss in practice, you are likely going to be 100 to 10000x times slower than the CPU in all cases, not the remote connection.