you don’t have to do a tempo marker for every measure. you only need to do tempo markers at the point where the song starts to become out of beat. sometimes that means more markers depending how often the song is not on tempo. however, this is just part of charting and there’s no easy way around it. it takes some time to learn and some skill to have in order to do proper tempo mapping. watch the tutorials, watch some videos, read some of the forum tips and you’ll be okay. but very few songs are perfectly tempo mapped out of the gate (although, a lot of current music seems to be produced, so it’s more likely to find tempo mapped music more frequently now).
You are about to leave Rhythm Gaming World and access the external songs DB. While no song or file sold for commercially available videogames is hosted there and only fan generated content is allowed, Rhythm Gaming World has no direct control over the database and no files are hosted here. Alright, we had to made you aware of this, now you can visit the database!