Tenbin provides tools to minimize the differences in execution time across shards. It uses the execution times of past test run when splitting tests.
For example:
shard default use tenbin
1/3 3min 4min
2/3 5min 4min
3/3 4min 4min
The optimization of the sharding algorithm is considered in E2E testing tools where test execution time is a more critical issue. In Playwright, this is being discussed in https://github.com/microsoft/playwright/issues/17969.