Difficulty of contracts, non-contract locations and roaming parties scales differently. Contract difficulty scales with time, the strength of your roster, the difficulty rating (skulls), the type of contract, and some factors specific to the type of contract – for example, escort contracts are generally more difficult the longer you travel, as it increases the chance to run into enemies. Contract reward also scales with the difficulty rating (skulls) of contracts, which is why it offers some indication as to the contract difficulty.
Artificially stunting your renown growth will only have you earn less money for contracts, but it won’t make them any easier.