what is the diff between chordal fillet and variable fillet radius?
Although you can vary the size of the radius on both functions, the variable radius fillet works by setting the radius value of the corner and the chordal fillet works by setting the length of the cord of the fillet (from the start point to the end point) see images
left fillet is variable radius from 5mm to 1mm right is a chordal fillet using the same values
Chordal fillets give a better visual radius as the width of the fillet is better defined
variable radius fillets have more extra options and are less likely to encounter errors when they are used around more complex geometry