 If you liked
Kumo desu ga, Nani ka?
|
 ...then you might like
Joou Heika no Isekai Strategy
|
Both MCs get reincarnated as spiders or something related to them, and they're focused on getting stronger, either using raw power or their minds (or both). They also end up in some sort of war against human race. In both mangas the MCs rely pretty heavily on strategies when in a battle.
However, Joou Heika no Isekai Strategy is way more brutal and gruesome, so if you don't want more than the level of blood and violent fights in Kumo desu ga I wouldn't recommed it.