My daughter naturally stopped taking an interest in milk in the day once we were properly established on solids and water. My supply did drop but it was still enough to keep her happy in the night, and if she ever did decide she wanted some in the day we had no issues. Our bodies adjust naturally :) my daughter also has eczema. We’ve just stopped breastfeeding at 18 months
It should adjust if you do it gradually
How’re you managing the eczema?
At this age your supply is well established so you should be ok, many people at this age don't feed or pump in the day whilst at work and make up for the feeds when they are home for example and the supply remains. And naturally toddlers tend to drop the day feeds first before nighttime. It would be recommended to drop the feeds gradually though so your supply can adjust, this will reduce your risk of mastitis etc.
Your body should adjust. My son day weaned around 13 months but I didn’t night wean until 17 months. And kept the sleep related feeds until 22 months.