The Indiana GOP would be stupid to try and destroy the Marion County or Lake County districts.
For all the talk about gerrymanders, Rokita when he was Secretary of State and drew the districts made them really common sensical drawn districts when you look at a map. The number of counties split is incredibly minimal, which if you're an anti-gerrymandering individual, is a good measure to have. My district the 3rd has 2 split counties for the whole district. I know the Democrat that lost in the 3rd (NE Indiana - includes the whole of Fort Wayne) in 2018 said in her defeat speech "always going to be difficult with gerrymandered districts", my response was "take a look at the red counties on the border of this district, from where were you going to get votes to take you from 35% to 50%?
The 2 districts at current that are Republican-held but are challenge-able for the Democrats are the 2nd district of Jackie Walorski (South Bend-based) and the 5th of Hamilton County (open race in 2020).
This annoys me as well. Gerrymandering has become a catch all excuse for every defeated Democrat. In some cases it is correct and there are indeed several states (declining number thanks to courts) that are R gerrymanders. However, just because a state is gerrymandered doesn't mean your seat is the one that is affected. In fact your seat might be made closer because of the gerrymandering.
If NC-09 was still centered in the Charlotte suburbs and exurbs, Pittenger would still be in Congress and winning general elections with ease. NC-08 was the seat that was gerrymandered to become more Republican.