They Both have romance at work and they are at office settings. ....................................................................

They both are similar because there is a secret romance between two coworkers at work. They both deal with gossips from other co workers.

Both of the little girls get adopted to a single man who has been through hardships. They both have cute girls as casts. If you liked one, you might like the other as well

the plot line sounds the same and I first thought the Japanese version was the prequel but its actually adapted from manga and the Korean one is from a webtoon.

the plot kind of sounds similar to me
The difference is that time hotel is a reality show and the 8 show is not. To be honest, I have't watched the time hotel but I think I should recommend this if you are looking for a similar theme/ plot. They sound exactly alike.