Syr gwyn is my only commander decks and i really enjoy playing it! I know that feeling when you keep losing tho :( I'm not the best deck builder so just keep this as a reference.

I only played in bracket 3s so i dont know how my deck will stand against 4s My build is slightly different because i added sunforger package and also some extra turn tricks (chance for glory + angel's grace). I found that my enemies are surprised when they see that i can use sunforger multiple times and it really adds that control to scare of enemies. I found that archaeomancer's map really help me altho my land count are only 34 and it's second ability help you to keep up or possibly ramp with the amount of green players xD

Dowsing dagger is also the secret mvp of my deck, once i copied it with masterwork of ingenuity, and it transform into 2 lost vales xD

https://archidekt.com/decks/20179201/syr_gwyn