Congratulations on graduating soon! And it looks like you work on a lot of fun stuff. You're likely going to have a lot of fun working on great projects over the course of your career!
I'm starting my answer, though, with a comment that your question (and opening sentence) don't really match the rest of your post. Why will be apparent soon, I hope. I'm also going to assume that "remote" implies that working hybrid isn't possible due to distance.
Your post title and opening statement lead one to believe that the most important desire you have is to work remotely. Likewise, you end with a question about what to work/focus on. But the entire body of the post is a bullet list of random things that you've worked on or enjoy working on.
So, my first thought is: what is actually important to you? Do you want to work remotely or work on what you are passionate about? Those are not necessarily mutually exclusive, but - for example - if you are most passionate about robotics, working remotely likely won't be an option.
Let's assume that your post title is accurate and the most important thing is working remotely. Why is irrelevant; you have your (valid) reasons for this. So, what can help you in this?
As noted, there are some fields and subfields for which this won't really be an option. Put those out of your mind if working on-site is a non-starter for you. And other fields will be more conducive to remote work than others.
Next, while you asked (or I inferred in your question) about tech, etc. to learn, my response is about traits. I'll assume you're smart and can learn anything you put your mind to and are interested in. If you land the job, I'll assume you're qualified for it. So instead, you want to know what you can talk about in an interview to better your odds of getting the job, but also can enable you to be successful at it once you have it!
The traits I'm going to list are ideal for any employee at any company. But they are MORE important for remote (IMO), because it's a lot easier + faster to spot dead weight in-office. Remote people can sneak by and cause problems for longer. So when I'm interviewing someone for a remote position, and I've already determined they have the necessary tech skills, these traits are where I hyper focus and give extra weight.
1. Take great pride in your work and always desire to present the best with every commit.
I will absolutely look at your code in GitHub and ask questions about it. Can you talk about something you wrote a year ago? If not (often I can't), did you leave yourself - and others - enough breadcrumbs and comments to figure it out again? Or is it a jumbled mess that you walked away from?
2. Don't let your fellow team members down.
You're still in school, so I'll ask about team projects. If possible, I might contact professors. It's not for everyone, but military service is a HUGE plus to me personally. I'm not suggesting to enlist, but if you were in ROTC (for example), be sure and talk about it. Did you have other experiences that were similar (volunteering, Big Brother/Sister, TA classes, ...)?
3. Be self-motivating and organizing.
Be capable of finding something interesting in even mundane tasks and manage yourself (work won't always be "fun" and sometimes you gotta just roll up your sleeves). Be able to organize the work, track it without constant oversight, and have the ability to take it to completion. If stuck or you don't know what to do, don't be afraid to ask for help and say so.
Note: if you find yourself at a company where saying "I don't know" or asking for help is frowned upon, get out of there as fast as you can.
4. Excellent communication skills.
I think remote work requires considerably more communication (of various kinds: email, DMs, PPTs, video) than in-office. To be clear, I don't care about things like being shy or speech issues (e.g., I stammer), but the quality of the communication. Your team shouldn't ever be questioning where you are, what you're working on, where it's at, what you're waiting on, etc.
I hope some of this helps.