I have to say that one minor but unfortunate aspect of this conflict is that we're not doing a great job of recycling an awful lot of lithium batteries.
EDIT: One thing I have been wondering about is the practicality of an FPV carrier -- like, a reusable winged drone, maybe with a deployable chute for landing or something, or a larger quadcopter -- that can launch an FPV quadcopter to do the actual hit. That provides range, possibly slashes time-to-target, and lets more parts be reused. The less that has to go on the vehicle that actually explodes, the better.
While you are of course correct on this, the amount of waste and environmental damage Russia is causing by blowing up dams and pretty much leaving a trail of garbage where ever they go combined with the pollution and wasted resources on burning fuel (both in engines and otherwise), destroying buildings and everything else going on, the couple truckloads of small LiFePo batteries on drones aren't even a rounding error in the equation.
I'm not an expert on what residual materials come from burning batteries, but I'm willing to bet that plastic from pretty much everything on the field has a bigger environmental affect, even the drones themselves are mostly just a plastic shell with very little of anything else in them.