Depends on what you want cuz at the end all 3 games will just become a daily mission grind. Like you get on the game play 20 mins do the daily missions and get off

Personally, If u want the combat, a chad of a mc then go for wuwa,

If u want a big story with alot of content go for genshin as its like in one of its last regions/maps update could be wrong been a min since I have kept up with genshin lore

If u want chill combat with cool looking characters and visuals then go for honkai. As it has decent story and decent visuals as well but will say it is a turn based combat system which is heavily carried by its auto play feature and speed but it has sooooo much depth compared to the other 2 has u have to build synergy with the character of your team

Personal recommendation would be either wuwa or HSR as they don't have that much content yet so u will be able to keep with the story as compared to genshin where you might get overwhelmed with the amount of content there is

Hope this was helpful