You can use our Android app on Windows via an Android emulator right now, the APK is available to download from our home page at pleco.com.
As for a potential native Windows port, the timeline is that we plan to release a Mac Catalyst version along with or shortly after the next major update to our iOS app, and if that's successful, we'll consider developing a Windows version (after we've finished porting that new version of our app to Android). If it's borderline successful, we might do a Kickstarter or some such for the Windows version and only release it if we make enough money through that.
The basic problem is that a Windows port is a *lot* of work (far more than Mac, which has gotten pretty easy thanks to Catalyst, at least once you have a fully-optimized iPad app) and yet we expect that most people interested in one would already own our mobile app and not be willing to re-purchase everything at full price to use it again on Windows. So we need to figure out if there's any price point for a native Windows version where we'd make enough money to cover the cost of development. That also includes opportunity cost - working on Windows means not working on something else that would grow our business - and the fact that going from 2 platforms to 3 means that every future update takes longer since we have to spend more time porting it.