What can one do in GTA 5 after completing the story?

You could explore the open world, try out different side missions, or engage in multiplayer activities.

You can explore the open world, discover hidden locations, and engage in side missions.

Well, you can try out different multiplayer modes or mods if you're into that. Another option is to start a new playthrough with different choices and approaches to see how it changes the experience.

You can explore the open world, try out different side missions, or engage in multiplayer activities.

After the story mode, you could try customizing vehicles, discovering hidden locations, or going for 100% completion by fulfilling various challenges.

After finishing the story mode, you might consider replaying it with different choices or going for 100% completion by fulfilling all side missions and collectibles. Another option is to check out fan-made challenges and competitions online.

You can engage in various endgame activities like raids, strikes, and PvP multiplayer modes.

Sure you can. Even after the story is done, you can freely explore the game world and engage in various activities.

After the story missions, you could focus on building your character's skills, customizing your equipment, or joining posses to tackle challenging cooperative tasks. There's also the option to discover hidden locations and unlock secret achievements.

After the story, you can focus on perfecting your builds, taking on challenging multiplayer quests, or exploring all the hidden areas of the game. There's also the option to aim for high scores and achievements.