A: Yes. Install via Desktop Mode, add the .exe as a non-Steam game, and force Proton Experimental. The touchscreen works for level editing.
A: Only if the level uses only base-game assets (no On/Off switches, no clear conditions, no 3D World style). Conversion is imperfect.
The primary way to get the latest, safest version is through the official developer community links. Official Devlog (itch.io): The most recent stable build (v3.4.4F V2) is available as a downloadable Windows executable Discord Community: Engine Kingdom Discord
There are a few alternative solutions that enable creators to experience Super Mario Maker 2's world engine on PC: