Not in playoffs game yet, I think every team that has secured playoffs ticket not take remaining regular season games too seriously to avoid injury so we will not see dogfight game for the rest of regular season.
Wrong. They must fight for a win until the end because it was counted on their respective "goals" and "expectations".
I will give you some of a good reasons:
-do you think a team that is expected on a 7th or 8th spot will not try to avoid the 1st spot or something like that?
-do you think a team that is expected on a 1st or 2nd spot will not maintained their position at the standing? like above question.
-do you think a team is not chasing for a homecourt advantage?
Make sense.

Yes there is some strategy in there.
They will be forced to play hard just so to get a spot where they will be playing a team with a chance of winning.
Rivalries, you will try to avoid this and aim for the team where you can match up your players with.
This is too deep, but coaches knows this also because of the scouts that keeps on feeding them information into which would be the best they should play against for a higher chance to go to the 2nd round.