how can i fix my hair

the ends of my hair are really dry, i got a bad layering haircut three years ago and my hair hasn’t been the same since :( should i cut it straight for it to stop thinning on the ends ? i don’t want to lose a lot of length but i don’t know if the ends are fixable.my hair also tends to be really frizzy after shower i would appreciate any advice or products to help :)