How to do powerful belts like Hayley Williams

I am a guy but I really like high belted females vocals like in All I Wanted by Paramore or the belted "I told you so" in Good Luck Babe by Chappell Roan. I have gotten better at hitting those high notes but really struggle to them sounding big and powerful though I have gotten marginally better over the past few years by just singing Paramore songs over and over again . I also never seem to have enough lung capacity. I must add that I have a heart condition so I do get out of breath quite easily which might make this harder.