I've recently discovered that I enjoy reading manga where the protagonist is from the modern world and is transported through some means to an underdeveloped but magical realm where they use their past knowledge to help better their kingdom/family. So could you please give me some recommendations to read?!

I'm new here but i have a suggestion: Feng Qi Cang Lan.
This is a manhua and is recently updating.
I think at about ch. 5 or so on its similar but not technically reincarnation more like the game world is in a "previous era". If you dont like this, dont hate me 😢 Also, what you requested reminded me of Qishi Huanxiang Ye. What can i say, I'm a fan of Manhua 😳 Some info about the cover - The guy in the cover is actually the girl's second account. I thought this facts was cool. Sorry, i just wanted to say that.

Enjoy. 😀
Isekai Yakkyoku- MC has knowledge on medicine.
Ascendance of a Bookworm- MC attempts to create books/library for the lower class.
E? Heibon Desu yo??- MC Tries to improve the land.
Koushaku Reijou no Tashinami- MC tries to improve the living conditions of the lower class of their land.
Jui-san no Oshigoto in Isekai- MC is a Veterinarian caring for otherworldly animals.
Knights & Magic- MC creates mechas that continue to improve on effeciency, utility and power.

If you like a modern world protagonist (in this case, a girl) being whisked away into another world by magical means, then you'd definitely like Kanata Kara. It's a perfect mix of action, drama, and romance and is one of my all time favorite mangas. I found it in my earlier days of reading manga, and it set some expectations haha. It's funny, because even though it's not that long (not even 20 chapters?) it's feels hella longer than most manga I read. Maybe because the chapters are longer?

Bleh sorry I'm rambling. Anyway, if you do check it out, I hope you enjoy it 😀

Red River doesn't really have an under developed world since the male lead is a prince but it does have the modern girl going back in time and helping save the kingdom and help those in need. Its actually set around the time of Tutankhamen and features recognizable historical figures like Ramses I later on. Personally it's one of my all time favourites. Another added bonus is its been completely translated and is long but not too long.

Thanks! 🙂 I have actually read some of the ones recommended so I'll try reading the ones I am pretty sure in knowimg that I haven't read.