This app was mentioned in 2 comments, with an average of 1.50 upvotes
This is the Singapore/Malaysia version - https://play.google.com/store/apps/details?id=com.playhit.our.kof.en.sgmy
This is where you get the china version - http://kof98ol.qq.com/web201509/main.shtml
I am actually also looking for an English guide for the KOF98UMOL game. I live in Asia and there is an English version of the game available for it. Not sure if it is available outside Asia but here is a link from the Play Store:
https://play.google.com/store/apps/details?id=com.playhit.our.kof.en.sgmy
I started playing the game about two weeks ago. It is pretty much P2W but I am toughing it out as a F2P. Currently at Rank 51. Leaving a comment here if in case there would be someone who could point us to an English in-depth guide for the KOF 98 UM OL game, preferably a subreddit or wiki. Enjoy the game. Cheers!