I look at dynasty teams in 3 year windows. No one has a clue as to what will happen in 2023. So IMO I don't value the 2.5 year age difference that much, since I think Evans and Godwin will both be solid WRs in the next 3 years. I also factor in that Evans has produced for years. Will Godwin do the same? I think so, but 2019 could have been a career year for Godwin.
If you think Godwin is worth that much more than Evans, then I can see that it's a tougher call for you. I disagree and I would do the trade.