I've seen at leat 16 out of those manga's here on mangago. Try to search by title ;)
I hope you're joking lol. Reijin Uno's the name of a manga magazine (麗人uno!). The name of the author's Misaka Niumu. They've done doujinshis before (which you can read in myreadingmanga) but they only made original mangas recently. https://www.mangaupdates.com/authors.html?id=40111
Manga updates page shows only two but you can check cmoa (三坂ニウム).
https://www.cmoa.jp/author/95194/ There are two pictures of Junai Dropout but it's not a sequel btw. One's just a full volume while the other's got 5 chapters posted seperately. :V The other two have different dudes.
HOW HAS NO ONE TRANSLATED MORE? Here’s the list of titles with pictures of the cover art from anime-planet:
https://www.anime-planet.com/manga/magazines/reijin-uno