Midwest - 6b, Lawn neglected for years and is ROCK solid and bumpy

I've owned my house for a couple years and now that we have less insane indoor projects to focus on I'm trying to restore my long neglected lawn. The soil is extremely bumpy and compacted. the only way I can describe it is like walking on solid upturned egg cartons or a mountain of golf balls. I'm planning to dethatch (first time in decades if not ever) and aerate heavily this/next month. Currently weeds aren't really an issue luckily but as i work on this I'll probably also overseed for bald spots and will be working better on ferts/water. I maintain a good mowing schedule and do water and fertilize but will be a lot more consistent moving forward

I don't want to add too much sand or soil when topdressing because the grade isn't great to begin with and I don't want to raise the soil level much. Are there any products or processes beyond aggressive aeration and maybe light sand topdressing in the spring that can help loosen up and especially smooth out the rock hard lumpiness?

Thanks!