I think a key problem is that things such as lockdowns that basically no-one would have thought would ever happen in 2019 did occur, and now that all those things were imposed on us, they hang over us like the Sword of Damocles as things that could happen again at some point or other. That's one way we really can't return to our naive state of 2019, as much as we might want to. The relationship between the individual and the state has changed, quite dramatically, and for the worse.
Another issue is that in 2019, other than those with specific medical conditions such as OCD, we didn't tend to look at other human beings as threats to our existence merely by existing, and we didn't have this wretched and poisonous idea that people who appear and feel perfectly healthy should nevertheless take mitigating steps (tests, masks, etc.) to be 'considerate' of others. In that respect our society in 2019 was, despite all its faults and issues, considerably better and healthier than now.
Also most things were quite a bit cheaper in 2019, and the inflation situation is about to get significantly worse.
Plus there are still all manner of things that I'm not allowed to do now that I could do freely in 2019. For example, while there are no domestic restrictions in place in England anymore, I am not currently able to travel to large parts of the world, including the USA.