to everyone thats struggling here, instead of all these complicated steps i have the simple solution for all of u. i assume most of u have spent hours to install many mods, only to realize the game suddenly gets an update and breaks all mods. this is what i hate too.
and once its updated, u have to go thru a whole day of hassle to install all those mods which is not straight forward.
now since ur game is already updated i cant do anything, but this solution if u r reading now u can keep urself ready before the next gta update.

however the solution is extremely simple and i found it by accident.

no need to use steam offline, or do complicated steps and edit steam data to prevent steam updates. thats just toomuch work. all u need is storage space.now follow my steps and no game update will ever break ur mods ever again.

1.so what i usually do first?
first i have the vanilla game, one by one i install all the mods like graphics mods to make sure everything is stable, stuff like texture replacement mods ,like LA roads, LA vegetation, car packs, plane packs,scene director, extended video export, everything.i install just the essential mods for me that are imp to create cinematics in gta.
other additional non essential mods i just keep it in a miscellaneous folder, so i can install or uninstall them anytime based on if i need them in my cinematic videos. i dont keep too many mods besides basic essential mods installed, coz we may never know which of those many mods could crash our game or make it unstable.
so i just install one by one, the basic most important visual mods along with texture and vehicle packs and properly test them to see if everything is fine and working right and all the mod combinations are working stable together.

so once im done installing all the essential basic mods and finished testing, that all my mods are working well together, i create a complete game folder backup and save it to my external hdd, so that anytime i install too many additional mods and something gets screwed and im unable to reverse it, i can simply delete that folder and replace it with my backed up one.

so now for the last MOST IMPORTANT AND EASY PART(based on my testing and what i understood)-

steam updates ur game, every time there is a game release.
now if uve followed my steps correctly and backed up ur game folder with all ur selected, essential mods installed, then the following will happen and u need to do.

for eg: u backed up ur folder as i said, now suddenly after 2 months there is a gta update on steam, now there is no way for u to launch the game without update completing.

so what u do now is simply just trust me, and let the update continue and finish.

after the update gets over, launch the game, then steam will show installing , then preparing to launch whatever bla bla...................

so after u launch the game and enter then menu, u can now exit the game.
after u exit the game, exit steam.

now remember the complete modded game folder bAckup i told u to make earlier? so if u did as per my example, u have ur game folder with all mods installed already backed up which was in a working state.
so now that u have ur game backed up.
u simply go to steam\steamapps\Common, and delete the complete "Grand Theft Auto V" folder, the one that steam just updated.

and then copy paste back ur backed up modded "Grand Theft Auto V" folder to that same place.

now just run the game as usual, either from desktop shortcut or from steam library>Grand theft auto v>play granft theft auto V

finally the points that u need to remember

the answer is, once steam has already updated a game, it stores that information somehwere. so it wont attempt to update or whatever, ever again unless there is another game update from the developer itself or unless u have manually tried to verify integrity of game cache.
given these 2 things, the game will never update.

nope u dont, the game will still launch coz steam is fooled into thinking that the game is in an updated state since u only deleted the folder and replaced with the backed up one.

now enoy ur game, and with each update that comes out in the future , let steam just complete the updates>and after that launch game>exit the game>delete game folder>replace it now with ur modded game folder and viola game runs. , no more broken mods.

just remember to keep urself backed up before each update gets released, so u can just follow my method and downgrade the game after it gets updated, with your backed up game folder.

enoy guys.

You can talk in more detail about the "gameconfig", I encountered many bugs such as crash when loading saves, broken quests and much more using the "gameconfig" from another version of the game, this is a very important note