Bokutachi wa Benkyou ga Dekinai!

it has the same start, a kind of smart (but most of all, hardworking) trying to help a group of girls to study and pass school. It has also this kind of harem but not harem feeling, and the funny parts in both animes are very great. The main character being very poor is also a similarity in both shows, and thats the start for both to start giving classes. 

Both are similar. Main male character smart but poor, u have ur harem that's good with one subject and is bad in other subjects. Both animes stay the same in S1, but it starts being it's own thing with its own uniqueness to it. Unfortunately it'll only came to light in the 2nd season which means ur gonna have sit through generic harem, school type of show with cliches overly done that makes isekais less common. How do I know this? I watched both shows and currently reading both mangas. Yes 5-toubun no Hanayome is getting a 2nd season. 

Harem animes both with the concept of tutors having a harem of their own unintendedly. 

both 5 idiot girls chasing the main charater . same vibe and humour 

Both of these have the same Study, Harem, and Romance vibe to the story. All of the girls need help studying while the protagonist is the one smart dude whos winning all the gals.  

-Both are Harem -Main guy tutors girls -Same premise They have similar premises and story, Main character tutoring the girls to get to college, the girls falling in love on him and etc.