Well exactly, Coal, oil and gas are presumably all "renewable" given enough time and the right climate conditions 😂
There are a few sources of renewable methane, principally via anaerobic decomposition.
Can also be made from atmospheric CO2 and hydrogen.
As with other synthetic routes to hydrocarbon fuels, the problem will be scalability. This said, where it is possible to collect methane and burn it, (e.g. from landfill, food and agricultural waste), it is environmentally better than releasing it into the atmosphere.