As a person that has struggled with a lack of motivation, I can relate.
I've tried a variety of approaches over the past couple years, but nothing has really worked.
It's good you have tried many approaches. Never expect the first - or first five - swings to hit. Like with depression, solutions can vary and may not come quickly.
You said a lot of things that are not quite related to motivation, so the whole problem could be much bigger. But you are saying that he is making plans for the future, and that he "goes out on trips and adventures" so I will avoid going on a tangent, and assume that the problem is truly a lack of motivation.
The first thing I would do is ask your friend what he wants from life, wants to do, wants to become, and then what he believes he could do if he had the motivation. Then ask him what he wants but doesn't believe he could do even if he tried, (or which would require excruciating effort from him).
If possible, list all of the answers down. It feels better to put things down on paper, and it helps gaining perspective.
Then you need to find out what prevents him from doing all the things he wants. You have given a pretty big hint here: he plays a LOT of video games (or at least, he used to). Ask your friend if he is spending too much time doing one thing, when he could be spending more time doing more productive things. Chances are that he is aware that he is wasting time playing games when he could otherwise be more productive, e.g. working or studying.
(From here onward, I will talk as if your friend is procrastinating by playing video games, but any form of procrastination should be equivalent. If, on the other hand, your friend simply doesn't have much free time, you might consider editing the question to make THAT more obvious. In my mind, it's difficult to be productive when you're already working full time and going to college. In such a case I wouldn't call the problem "a lack of motivation", but rather "trying to do too many things that aren't very fun just to get by, and feeling overworked as a result")
If your friend truly has ambition, he should be frustrated at himself, and you should be able to tap into that frustration to help him overcome his procrastination issues. There are a few ways you can help him.
Create a schedule
Our brains are more productive when doing habitual tasks. For instance, at first we can be reluctant to brushing our teeth every day, but after years of doing it, it almost feels wrong not to do it: our minds build habits. Habits are a way of removing some cognitive stress by mentally preparing to do something (as opposed to continually "choosing" to keep working).
Create a schedule that is fairly easy, so that your friend has very little reasons to burn steps. As time goes on, make changes to the schedule so that it is more restrictive and includes more productive time. If the schedule is too restrictive, don't feel bad to make it less restrictive: a schedule that is not respected is the worst schedule.
Simply moving the time zone for playing video games from "anytime" to "from 2PM" can actually make a world of difference.
Your friend obviously likes to play video games a lot. Like anyone with a powerful habit, it can be very difficult to "just stop". Fortunately, you friend has you.
I've often wished that I could ask someone to "keep me away" from games during my working hours. If you agree with your friend to initiate this mechanism, it could work, although be sure that he is okay with it. Think of it like detox, but for entertainment media.
More extreme versions of socially-enacted deterrents are called "Commitment contracts", where your friend gives you control over a certain amount of his cash, which you then are to spend arbitrarily if your friend does not act productively. (The YouTuber Boyinaband made a video called "The Happiness Experiment" where he essentially did this with his sister. Her sister would give 10K$ to the Church of Scientology if he was not productive every single day!)
There are tools to lock applications or websites on the computer at given times of the day. I use such tools myself.
These deterrents are all about relieving stress from having to constantly choose to "keep on working". Dedicating a specific room for productive work can help. Putting your game consoles and computer games in a separate room where they are not apparent or nearby can help. This beneficial effect is actually shown in the famous "Marshmallow experiment" (google it!).
Keep on planning
Planning is usually pretty easy, especially if it concerns planning things that will happen tomorrow or later (after all, to procrastinate is to plan to do things for later). Take time to plan things out with your friend; just putting plans on paper can help a lot in "making sense of it all".
A mistake a lot of people do when making radical changes in their lives is to go all in very quickly. As with the Agile mentality, it's recommended to make planning a continuous process rather than a one-off thing. Buy yourself a chalkboard, or download time-tracking applications. Dedicate 15 minutes every day to sorting out what you'll do in the near future, check boxes to keep track of what you did and did not do, etc.
Even large and abstract tasks (like "getting a girlfriend", or "finding a more fulfilling job") can be broken down into smaller steps ("get comfortable talking to girls" → "learn how to start a conversation" → "practice social interactions in the mirror/filming yourself/with supportive friends") until they seem achievable.
With a good workflow and some discipline, nearly anything can be achieved.