Error when serving after upgrade to SPFx 1.21.1

[ivonool]

Hi

I've stumbbled on an issue after upgrading project from SPFx 1.18.2 to 1.21.1. Gulp serve runs fine, node_modules, lock files have been deleted multiple times and everything has been reinstalled.
Project contains multiple components - webparts, field customizers, command set extensions.

When executing npx fast-serve --config=myCommandSetConfig follwing issues are in console:

Any ideas?

[ivonool]

I tried to downgrade to SPFx 1.20, still same issue.