The contrast thing is only to stretch your perspectives, it's not about good or bad, it's about understanding other perspectives and the minute shades of grey that you might eventually see. Regarding extremes, it takes time, DBT is Dialectal behavioural therapy, but the more important part is the word: DIALECTAL, because it sums up to two truths, because two things can be true at the same time, someone can be irresponsible and kind, or mad but mean well. This is something that takes time to practice and focus on, it's taking me 3 years, and I'm probably 50% there. And positivity isn't always good, sometimes it's better to see bad and understand that it's bad. If you're always happy, you're in denial or perfect, and I trust neither, but if you're happy and sad at times, that's the only thing that's reasonable. Quick last note. Practice doesn't make perfect. It makes permanence. Remember that till you pass.

I look back, realise that I'm still young, ~20ish and that even if I'm not going somewhere I know of or have certainty in, I have to take the steps to go where I want. Regarding your lack of enjoyment in things (Anhedonia), it's a waiting game, at least for me, because I can't enjoy what I used to, but I know I did at some point, so I make sure to keep my physical health at baseline, 3 or 2 meals, especially if I haven't eaten all day and I'm still not hungry, medication if I'm on any, water when thirsty, go out if I have obligations/responsibilities, and your physical health will be a safety net for when you mental health dips, Also, go into rabbit holes, learn something new about a creative art like photography's rule of thirds or how a Camera works, they can change how something looks in life sometimes, and if you want to sleep all day, so be it, sleep, Eat and fulfill obligations.

Someone else mentioned taking leisure as a good thing at times, If you have no obligations to fulfil; like work, Understand that leisure IS now the new obligation. Like on a weekend where you have nothing to do, treat enjoyment as a task to complete, because if you're struggling to do so, it is a task now. sometimes taking a day to enjoy your day is something that's difficult, and therefore, should be a objective to be proud of, personally, I've had that and so have mental health professionals I've talked to.

I'm also spontaneous, so a 2hr train ride by myself or with a friend that has planning from the night before just to get food is sometimes pretty fun.

Btw, not a professional, but keep practising mindfulness, or other DBT skills, or just check out DBT, it's useful for day to day stuff and not specifically for a certain diagnosis. If you're trying to change perspective, keep learning and practice techniques and skills, think in extremes then another extreme then contrast the two and think of the juxtaposition between each and find the middle ground... For an extreme format of perspective shifting, but don't get lost in the sauce of things.

Additional notes about anxiety (TW?), I'm kinda extreme, so I did exposure therapy on my own, or negative mindsets to understand that anxiety is pointless to think about if everyone is thinking the same thing, but it can go deep and dark if you're not careful.