It depends on your pool. It's possible they may not be active because they're getting tons of rejected/stale shares, that they're simply not actually mining, or the pool requires shares to be confirmed/out of a round before they count your hash rate.
When I check a random inactive worker miners, they're all working fine, without errors.
But what would the advice be, to maximize my hashrate, converge all miners into 1 single worker or spread them among multiple workers?