Summary of judgement is easier to achieve for civil remedies against claims against the law enforcement since a very narrow construction is used for a wrong having to match the facts of a previously ruled case. Therefore, challenging qualified immunity on a case by case basis is probably not very effective that way.
But if a case is considered on the merits, and cannot be thrown out, a judge may get a chance to reach a finding that a certain action would be in violation of the law and/or the constitution, and next time, that declaratory relief could be used (by an estoppel, or as case law if on appeals).
Is this a valid strategy to set get decisions on undecided cases to prevent them from reoccurring?
If not, is it because non-appellate courts decisions may only have an (judicial, collateral etc.) estoppel effect and won’t become binding law, and law enforcement agencies would rather not challenge district courts decision?
If not this, what is the reason? Or has a strategy like this been used to draw the boundaries of law enforcement operatives?
Law enforcement violence as used in this question should be read as the willful use of unnecessary or excessive violence or force under for e.g. such that would be in violation of the International Covenant on Civil and Political Rights (the "ICCPR") as understood by customary international law or binding precedent of international courts.
From the Wikipedia on the compliance of the U.S. with the ICCPR:
"In 1994, the [UN]'s Human Rights Committee expressed concerns with compliance [by the U.S.]:
Of particular concern are widely formulated reservations which essentially render ineffective all Covenant […] rights which would require any change in national law to ensure compliance with Covenant obligations. No real international rights or obligations have thus been accepted. […]
Indeed, the [U.S.] has not accepted a single international obligation required under the Covenant. It has not changed its domestic law to conform with the strictures of the Covenant. Its citizens are not permitted to sue to enforce their basic human rights under the Covenant. It has not ratified the Optional Protocol to the Convention against Torture (OPCAT). As such, the Covenant has been rendered ineffective, with the bone of contention being United States officials' insistence upon preserving a vast web of sovereign, judicial, prosecutorial, and executive branch immunities that often deprives its citizens of the "effective remedy" under law the Covenant is intended to guarantee.