Advice for outdoor swivel chair seat?

Have two swivel outdoor chairs that I think I found on the roadside. They have rotted canvas seats but the rest of the chairs are metals and in good shape. What would be a good way to replace without having the seat sag or look super DIY and cheap? I have seen some paracord macrame seats but I’m not sure I could manage that. They are bronze looking metal. Looks like the old canvas was secured by a type of grommet but they are round with no screw head on the back…not sure if they will come out. Anyway, suggestions (especially ones that are DIY and with photos) appreciated!