Steam charts might be the same, but exploration statistics from EDSM are both more precise and representative of exploration activity. Number of new systems discovered per day, number of bodies scanned per new system, and, curiously enough, even ELWs / systems: all of them are under half of where they were during DW2, and by now, considerably under the time of the Return, too. (Let's not forget that EDSM didn't have data from console users then.)
However, we do have a bit more data, that's entirely official: exploration CGs. As you'll see, there has been a long pause in those, but we've now had two after Chapter Four and the introduction of the FSS.
Let's see...
Interstellar Initiative: The Enclave, Phase 1, 3305 July: Thargoid storyline: 3,879 contributors, 597,895 reports.
Exploration Data for Research Centre, 3305 February: set during DW2, back in the Bubble: 2,654 contributors
Children of Raxxla Appeal for Exploration Data, 3302 December: Salomé storyline, two concurrent CGs: 3,915 contributors
Federation Appeals for Exploration Data, 3302 December: Salomé storyline, two concurrent CGs: 3,546 contributors
Federation appeals for Exploration Data, 3302 September: Thargoid storyline: 7,780 contributors
80 DD-D 774-CE-2 (Jaques) Appeals for Exploration Data, 3302 September: CG lasted four weeks, Jaques storyline: 7,471 contributors
Searching for Barnacles, 3302 July: Thargoid storyline: 8,224 contributors
Exploration Data for Utopia, 3302 June: 6,425 contributors
Jasmina Halsey appeals for exploration data, 3302 May: Federal storyline: 2,096 contributors
Mapping the Cosmos: Planetary data, 3301 December: 5,173 contributors
Doesn't look like the FSS was a big success in getting more people to do exploration CGs, either.