Fat loss frustration

Hi. Looking for reliable advice. I’m 57 female, and 4 months into a body recomposition program. I lift 4 times a week, do HIIT twice a week and walk 5km 2 to 3 times a week. I’m on 1800 calories a day, so in deficit. My body is shaping up well but the fat around my middle just refuses to budge. Getting really frustrated now. I know it’s age related, but does anyone have any tips?

Regular swimming can be helpful for the tummy & abs area. Walking is a good workout but doesn’t do much at all for that tummy area.