The first two-thirds of Kasei Madoushi no Isekai Seikatsu‘s fifth entry are rather difficult to get through. For some reason the author decided the main plotline here would be idol-centric, which does not fit the setting at all (though to be fair they did make an attempt to camouflage it a bit). The last third however is quite good and provides some major advancements in the main couple’s relationship.
The fourth Shinigami ni Sodaterareta Shoujo novel is much like the third in that the battle focus is split between Mekia and Fernest’s forces. This entry mainly seems to be setting things up for the endgame with the upcoming follow-up looking like it will be the calm before the storm.