So I was trying to replay this gem of a game the other day and was running into problems left and right troubleshooting the install for it alongside adding mods to it, It took some trial and error but I finally got it figured out. if the other steam guides work for the rest of you then great, but they didn't work for me so I'm guessing they no longer work

So firstly just to simply install the game and play it vanilla with the dlc requires you to install it through steam (assuming you own it through steam) DO NOT INSTALL IT THROUGH THE EA APP OR THE GAME WILL NOT BOOT. If you boot the game you'll notice it runs but you don't have any dlc available, so what you need to do next is if you don't have the ea app you'll need to install it, once installed and logged into your ea account, find dragon age origins in your library, open up the game options and repair your files, make sure you do this through the ea app. repairing through steam accomplishes nothing. once you're done repairing your files you should have access to all of your dlc. If you wish to play the game vanilla, you can stop here.

If you wish to mod then I recommend going into both steam and the ea app and turning auto updates off, you can't fully turn them off on steam as it will try as soon as you boot the game through steam,messing up your game and forcing you to restart the repair and modding process. So I'd advise either making a desktop shortcut to boot the game directly or booting through a mod manager.

4GB patch
So I highly recommend you get the 4GB patch as it will help with game crashes, there is a guide for this on steam already but it always seems to break my dlc so I went to this site here: https://ntcore.com/4gb-patch/ and downloaded this program, the you go to C:\Program Files (x86)\Steam\steamapps\common\Dragon Age Ultimate Edition\bin_ship in your pc files and find the daorigins exe file and select it. now you have the 4gb patch

next is mods, there are guides on manually installing your mods if you wish to do it that way (some mods require it) but most mods can be done with a mod manager. now I mostly do minor tweaks to my game like bugfixes and simple quality of life stuff, and for that vortex by nexusmods works wonderfully, it is super convenient as it allows you to scroll through nexusmods and click on the mods you want and click to use mod manager when downloading and the mod manager will install the mod and you're good to go. if you're having trouble with vortex then maybe try transitioning over to the dragon age mod manager. be sure to always read the install instructions and mod requirements when installing. failing to do so can break your game. also as unfortunate as it is, I advise against using mods to improve the graphics and textures of the game unless you really know what you're doing or are ready for some major trial and error because this game has a tendency to crash when overdone especially inside of denerim.

also lastly this game has a memory leak, you will notice it get worse as a play session goes on, you'll notice things like enemies taking longer to drop their loot due as the main tell tale sign. there is no legitimate fix for this other than saving your progress and exiting the game and then rebooting it. hopefully this helps someone struggling.

guide for enabling the console
I'm going to list some information pulled from the dragon age wiki for you to use

Ultimate edition
To enable the console in the Ultimate Edition you have to edit the file DAOriginsLauncher.xml.

For steam in "Program Files (x86)\Steam\SteamApps\common\Dragon Age Ultimate Edition\data"

First create a backup of DAOriginsLauncher.xml. Then go to the Steam library, right click Dragon Age: Origins - Ultimate Edition, choose Properties, choose the Local files tab, choose Browse local files, and enter the path of the data folder. Open the file DAOriginsLauncher.xml with a text editor (Notepad++ works well). Use Ctrl+F to find the following line:

<true action="execute" file="${BINARIES_DIR}\DAOrigins.exe" path="${BINARIES_DIR}" autoquit="true" />

It is probably line 184. Between autoquit="true" and />, add:

arguments="-enabledeveloperconsole"

The line now reads:

<true action="execute" file="${BINARIES_DIR}\DAOrigins.exe" path="${BINARIES_DIR}" autoquit="true" arguments="-enabledeveloperconsole" />

Save the file.

Ultimate edition: Alternative method

For some people using the Ultimate Edition the first method may not work, for example if you are not using the launcher and using the .exe directly to start the game. For these people, find your Dragon Age: Origins Shortcut (assuming you are using a shortcut to the .exe on the desktop), right click,and select properties. In the "Target" box, add -enabledeveloperconsole at the end of the line and save. For example:

"C:\Program Files (x86)\Steam\steamapps\common\Dragon Age Ultimate Edition\bin_ship\daorigins.exe" -enabledeveloperconsole

This should work if the first method does not work.

I could be wrong but I think you need to do both methods if you're using any mods as booting through steam will cause it to try to update and "fix" modded files

If you've never played the game before I recommend you play through it naturally once, but if you're a returning player and want to have access to the various gear unlocked through achievements you can use the console command "runscript cheater" to unlock your achievements and thus unlocking gear for future playthroughs. you have to do this in game though so you have to start a new character or load an old one, run the command, it should say success if done correctly, and then any new characters will start with the unlocked gear. pre-existing characters will not gain access to the gear

some special mentions for mods that are a must have for me

No helmet hack- allows you to toggle the helmet on your character without losing the benefit of having it equipped

Quinns ultimate dao fixpack- bug fixes and such

Unlock Specializations- unlocks all the specialization classes for you, maybe if you haven't played the game before you try a playthrough without this but generally speaking I install this because anytime I uninstall this game and reinstall it later on I don't want to have to back and unlock everything again.

Madd gift guide- many gifts in the game are designated for a specific party member, this will flat out tell you who it's for which can be super helpful