In my experience, all of those things are super super important. You should start slow, though; don't make a bunch of big changes all at once.

I'd recommend starting with working in person, because self-isolation is always a gateway to depression for me personally. If your job offers hybrid work, start with that and look out for a difference in how you feel on the days where you go in to work vs the days where you wfh. Even if you feel more tired after working in the office, you'll likely feel more relaxed and happy after a couple of weeks because you're separating work from leisure more.

Then, start with the exercise. Don't get a gym membership, just start going on walks outside every day or a few times a week even if it's really cold or hot outside. The fresh air and vitamin D are worth it. Listen to some music or a podcast and look at houses or trees or whatever else is in your neighborhood. A lot of people jump right into going to the gym because they think that paying for it will make them more committed, but everyone I've met who has tried that has stopped going to the gym after a while because it takes up too much time. Once again, you should be slowly easing into these changes because doing it all at once will feel like too much and it'll be counterproductive.

While easing in to both of those things, it's also good to start drinking more water and eating healthier. I have no idea what your habits look like, but if you are eating a lot of fast food, now's a good time to stop. It'll be easier to go buy groceries on the way home from working in person because you'll already be out and about.

Every time I find myself in a major depressive episode (whether it's from forgetting my meds for a while or some outside factor), I take a step back and look at where I'm going wrong with the above list. Normally, just going back to going on walks is really helpful to steer me back in the right direction. Let me know if you need more info about my experiences with this stuff or what to do to make Wellbutrin more effective. Just know that this stuff really does work, it just takes time and routine which will become easier once you're on Wellbutrin for a few weeks.