add clip on edit page - by default inspector has Zoom X Y, position X Y, cropping, dynamic zoom
so can do a lot without needing effects - one thing can't do is rounded corners - needs Transform effect
(cropping - default is 0, max crop left is 1/4 of vid width eg for 1920 max left / max right is 1920/4 = 480
max top / max bottom is 1020 /4 = 270
max crop = nothing left to see
Resolve FX Transform has position X Y, Zoom, round corners