The first Saiaku no Avalon novel resembles Shujinkou ja Nai! in some ways, such as how the main character takes over a side-character’s body in a game world (although it’s an antagonist rather than an ally in this case) and the way his sister seems to be far more powerful that he is (when not using exploits). Main difference being that this MC is focused on becoming a protagonist on his own behind the scenes instead of trying to avoid it by raising others up.
Tensei Kizoku Kantei Skill de Nariagaru‘s third installment appears to wrap up all the key battles of the war, setting the stage for a potential upcoming kingdom-building segment. Quite a few overpowered retainers have been acquired at this point and I’m not really sure what kind of future event developments could even even pretend to threaten them.