For trans people it depends.

If you're just starting estrogen-oriented HRT and you're at a weight considered ideal for your pre-HRT body, then it is helpful to actually gain a few kg of fat, together with weekly hours of intense activity (like running, bicycling, squatting and planks, hip thrusts) coupled with moderate activity (like walking half an hour everyday) Then fat redistribution will be more effectively towards a )( body shape, with breast growth improved during the first year(?). Progesterone may aid in the last as well. This guide may help.

For testosterone-oriented HRT, I'm less certain, though I assume the fat redistribution's accent is more strongly on fat loss, and exercise for muscle growth. Lifting, bench presses, planking, and the like for \/ bodies. Don't forget leg day! Here's a good training scheme.

That said, everyone has their own goals; important imo is that one remains healthy. A good diet is balanced and lowly processed, containing plenty vegetables and some proteins and water. And have a rest day. A nice fist rule is 4 days of exercise anywhere in the week and a day or two of relative rest.

A body fat percent healthy for all people (binary and nonbinary) would be around 14-25%. If you can get pregnant (and seek to do so), it's better to be a little higher in this range, because during pregnancy, your body will prioritise the embryonic/fetal needs more than yours.