First of all, the "eth" asset exists in different forms across Ethereum and Polygon. For each blockchain, we have one utility token and other erc20 compliant tokens (+ other standards).
eth - the utility token
weth - the erc20 wrapper for
matic - the utility token
wmatic - the erc20 wrapper for
weth - an polygon erc20 representation for polygon
eth that was bridged from ethereum mainnet
Second of all, any transaction requires gas paid in the native utility token of the chain. So for ethereum you will pay native
eth, while for polygon you will pay native
Regarding your bridging question, if you ask to be paid in
weth on Polygon, you will receive (#5) the polygon erc20 weth token in your wallet. To bridge it to Ethereum Mainnet you will use a service such as the Polygon Bridge or Hop Exchange. These will convert your polygon weth -> to mainnet (pure) eth.
For Hop you will need to sign one transaction on polygon (requiring utility token for gas: matic) for the transfer.
For the Polygon Bridge (from what I remember) you will need to sign two transactions. One on polygon (requires matic) to send the polygon weth and one on ethereum (requries eth on mainnet) to receive the weth. For this you need to consider having some eth for gas on mainnet in the account before starting the transfer.