No, generally you should have a great experience. Be mindful though, if you’ll be using Rack Pro as VST in a DAW, you need to match the architecture (ARM64, X64) of Rack and the Daw correctly. Not all combinations are valid. You need to read the documentation of your DAW. Rack will run just fine with either architecture (X64 under Rosetta2). You can even install both architectures of Rack on the same computer, by renaming and installing in the right order.
No. I maintain a list of the (currently 27) Rack plugins that are not yet ready for ARM here. Only really two “big ones” and they should be coming to ARM. But like I said above if you really need it you can run the X64 version on the computer as well. It shouldn’t be an issue for you, unless you want to run other people’s patches, where they have used one or more of those plugins.
Yup. Enjoy your beautiful machine.