I think both shows need to be watched if you like AI/SCI-FI related themes. Steins Gate 0 has Amadeus - computer AI with memories of Kurisu while Ghost in the Shell has Makoto Kusanagi who is an android with a human brain but no recollection of the past. Ghost in the Shell has a lot philosophical commentary on what it is to be an android/human and what is the boundary between them.
In both series, the mc has someone he loves/idolizes died, and this first make the mc depressed but then also become his biggest motivation throughout the show. The person died also still appear in almost every episodes and play important roles in the plot even after their death. The difference is TTGL is more shounen action and Steins Gate 0 more sci fi drama. But both series are pretty good to make you more high spirited and less depressed.