1.20.6 Eclipse missing all packages

[Tiny Desk Engineer]

I managed to import the 1.20.6 MDK into Eclipse, but Eclipse is constantly complaining that no types or imports are valid even though I haven't modified anything in the project yet. It's important to note that running gradlew build results in a working mod jar, even though in Eclipse nearly every line has at least one error on it, so presumably this is a problem with Eclipse itself, not the project as a whole. I've been trying to fix this problem for over 2 weeks now and haven't made any noticeable progress. I've tried running every Gradle task I could possibly think of, including some that aren't even included in the version of the MDK I'm using. I've looked all over the internet for potential solutions, yet none of them have helped. I've made no visible progress ever since I got the MDK into Eclipse. I followed the instructions at https://docs.minecraftforge.net/en/1.20.x/gettingstarted/ as well as those in the README included in the MDK.