A repro of an issue in Gradle 7.4.2 (and other versions) in which having a repo with onlyForConfigurations as the first repository can cause dependencies to get resolved in a single thread rather than in parallel.
Try running the following (adjusted for your OS if necessary):
# Clear Gradle's dependency cache so it needs to re-download
rm -rf ~/.gradle/caches/modules-2/
# Run a task that requires many dependencies
./gradlew resolveAsTaskInput
When the onlyForConfigurations repository is first, Gradle will show that all the dependency resolution is happening in a single worker. When the other (mavenCentral) repository is first, some of the dependency downloads happen in parallel across multiple workers.
In this repro, the timing difference is not quite large enough to be obvious, but in certain situations the single-threaded resolution can be over a minute slower.