You should love her and accept her as she is. Look up body positivity. When she wants to lose weight, she will. We live in an appearance based society and we conditioned to prefer pretty, skinnier people. You should let it go.
My Dad is like this too and it’s annoying because every time i see him, he’s always like you should lose weight, that red dress you wear makes you really fat, you are really fat. It pushes me away from me and he only focuses on my fat and not me. All of our conversations revolve this.
Nothing is enough for my dad. You should be grateful that your daughter is independent, has a job, can live in her own place and drives. You want what’s best for her, look beyond the weight, look at her personality and qualities. Maybe look inside yourself, what is bothering you? Is it that she is not going to find a husband ?