Basically the show is having TNG cast reuniting and communicating with each other in a well acted, heartfelt and sometimes emotional dialogue surrounded by idiotic plot.
The scene where Data is using his memories to conquer Lore seems dramatically powerful but it's nonsense that Soong decided to put both of them in a single body.
You get stuff like Picard having an emotional heart to heart communication with his son Jack to fighting assimulated that is well-acted and well written. However the whole set up to get there doesn't make any logical sense.
The plot where the Borg needed Picard body because Picard's body contained gene was modified when he was assimulated which allowed his body to be a transmitter to the borg which will be used to assimulate the Federation seems idiotic. This is because there is nothing special about Picard, the special gene was there because the Borg modified Picard gene. If the Borg had the power to modify Picard's genetic structure they can modify anyone else and hence don't need his body.
Then the Borg had shields down and letting the TNG crew on theship with the crew implying this is too easy and must be a trap and no trap occur. Then you have an understaff Enterprise D (only containing the bridge officer) taking on a borg cube single handedly (compared this to Star Trek III where the Enterprise A was clearly handycap by not having a full crew). Yeah it was cool to see the Enterprise D return and seeing the TNG recast to its return but the story doesn't make sense at all.
While the PIcard/JAck crusher dialogue seems emotional and well acted, it completely destroyed the Borg.
Directly stating that Picard's son can escape assimilation if he "choose to". Then having Picard connected to the borg system to have a heart to heart with Jack and with the power of love convinced Jack to reject the Borg and become unassimulated. No matter how well acted the scenes are it ruined the borg and Jack and Picard character.
A) Why wasn't Picard assimilated when he connected to the collective
B) It weakens the Borg as a villain
C) it creates moral agency to all the people who were assimilated. They weren't powerful enough to resist to fight off assimilation. Why shouldn't Jack Crusher be put in prison for killing thousands of people if he had a "choice" to reject the Borg (also he was responsible for being assimilated in the first place as well due to his idiotic action).
I think the praise for this season is simply the contrast between the first two season and the last season rather than being a quality show in its own right. The first two season was pure contempt to Star Trek franchise. The third season had nostalgia celebrating the franchise that seems somewhat genuinely loving. It has great moments but as a whole it's poorly written show.
Let say Picard Season 1 is 0/10. Season 2 is 0/10. Season 3 may seem great when it is a 3/10 compared to classic Trek