Senjou no Valkyria, Nejimaki Seirei Senki: Tenkyou no Alderamin Recommendations
Both series has a strong female lead and capable male lead that although the male lead lack in strength, they make up their lack of strength with intellect and charisma. The two does share a lot of similarities. If you like one, you are definitely bound to like the other.
The Main characters in both anime series do not want to get involved in war, but due to their actions manage to get themselves involved in the war.
Both series are set in an alternate "world war" scenario, where the main character is forced to command a team of soldiers to fight, despite actually disliking war. The main characters in both are also slightly quirky, sticking out from their comrades and showing great strategy and leadership skills. Valkyria Chronicles has a similar setting to world war 2, with tanks, however Alderamin goes for a slightly 'steampunk' approach with canons, rifles, airships and sword fighting.
The animation style between the two shows also feels slightly similar, and the character designs are often colourful. They both have a similar feel, and if you enjoyed
Both take a over look on military battle and strategy. Both have a magic aspect in. They also don't glorify war and show the pain of wars Nejimaki is not as long so story is not as complete but bother very good animes.
Strategic Sloth Main Characters? ✓
tsundere style fighting female lead? ✓
Love Triangle? ✓
War setting - albeit different period ✓
Evil political agendas? ✓
Valkyria is a masterpiece and thankfull Alderamin has many similar traits that may potentially entice viewers to watch.
Both shows are set on alternative realities (could be compared to 19th-20th century or so) with some magical, supernatural beings while they aren't the only/main focus of the show
Even though the main male characters are a bit different when it comes to their nature they are both great tacticians and were both forced to fight and the setup of story is also somewhat similar. There is also at least one mentally and/or physically strong main female character in both series.
The main focus of both shows is military even though it isn't following the reality that strictly. For example there are plenty