We study TFMs in the presence of heterogenous transactions and computational nodes. Our first set of results show that multidim fee markets (such as EIP-4844) fail to achieve good guarantees as heterogeneity increases. We complement this result by introducing the Broker Mechanism, which works in the fully heterogenous setting. This mechanism is suitable as a market for sharding computation, delegating computation to off-chain nodes (prover markets and coprocessors), and allocating preconfs.