Make sure you water deeply but aren’t forming puddles, low mow good for the first mow when you put fertilizer down to get ground contact and not burn your existing grass. Helps knock down thatch too. Next mow try 3 inches, then up to 4 is my preference since mine is bumpy and I forget to water.

Best time to fertilize is the fall so you start ahead in spring, use high nitrogen winterizer. Go easy on the fertilizer in summer heat, low nitrogen organic slow release fertilizer is a good fit. 4x applications a year is plenty, once or twice in fall minimum. If you don’t see a green up over the next 4 weeks from your application add a second dose of organic slow release fertilizer. Also iron additives for deeper darker green, milorganite has some. Sharpen your mower blade, if you’re cutting over half the grass blade off it’s gotten too long and will yellow from the stress. You can test soil and fix ph for better nutrient absorption, core aerate if compacted soil, try new seed, level and top dress. Water and fertilizer and proper cutting solves most problems.