Lethality is important, but the goal at the strategic level should be to end the opponent’s will and capability to fight. Destruction and death aren’t always the best way to do this.
https://www.youtube.com/watch?v=hkD-cbAVDa4
Early modern armies knew about trenches and fortifications and used them often, but these wars didn’t turn into WWI style trench wars because trenching takes a lot of labor and locks in positions that the enemy can just go around. There were fewer scenarios where you could know that the enemy would attack you in a particular position, so building a trench would just get you avoided. Part of warfare is maneuvering around and trying to start a battle when you have the advantage, but if you want to engage the enemy, they wouldn’t fight you if you are entrenched in too strong a position, unless they had to.
https://www.youtube.com/watch?v=zfxcgJsEWY0
Flanking isn’t that easy.
https://www.youtube.com/watch?v=dd0fCuBPlno
Ukraine Strikes Russia’s Bombers – The Operation, Damage & Lessons of Ukraine’s “Bear” Hunt
https://www.youtube.com/watch?v=MPXs2wDv4Kc
Hamas’ October 7 Attack: The Tactics, Targets, and Strategy of Terrorists
https://www.youtube.com/watch?v=Gh5MZfBrvbE
https://www.yahoo.com/news/false-canopies-fighters-one-almost-170407096.html