Hi @syinkim,
I am sorry for the complications you are facing, I am working on getting the root cause fixed, however I have good news for you:
From your screenshot I can see that you have the master branch of the knime-sdk-setup project checked out. This is meant for developing extensions for the upcoming 4.4. release, and requires java 11 (see Preview KNIME AP 4.4 -- Java 11 & Eclipse Upgrade). As you have encountered today, this target platform can be a bit unstable.
If you want to develop plugins for released versions of AP you need to switch to the specific branch (e.g. releases/2020-12 for Analytics Platform 4.3), then set the target platform again.
best,
Gabriel