New fiberglass batts near HVAC ducts
Those ducts are flex ducts they do have insulation in them but it is limited.
If you have enough length in the flex duct I recommend adding insulation under the duct because the flex duct is not hard to collapse.
The ducting is lightweight and although it will slightly compress the additional insulation the new insulation will work better if it can be laid continuously under the duct.
Where the duct is at the roof if you don’t have enough slack to put underneath stop right at the duct for best results.