I think it is possible, in case if company has office. I think when we are talking about "remote", we need to pay attention to tax residence. Last week I got the offer from one of FANG and had to decline the offer due to remote work allowed only in countries where the company has an entity. So "remote" !== "Anywhere", in my case, the company proposed to me relocate to a country where the company has an entity, live here (to get tax residence), and work "remote".
This is a really tricky question, I am helping several open source projects with a huge number of stars and downloads. I did more than 500 PRs and most of them in popular projects. And I have to say a not popular phrase - in most cases, OSS is not a story about big money. Even more, it is really hard to replace a full-time job by working on OSS. After almost 3 years involving in OOS, I noticed the following things:
1. In most cases, the popular OOS project has a team in some large companies, for instance, React (Facebook), Angular
(Google), VSCode (Microsoft), etc. and that's mean that code is open-sourced however a key decision made by an internal team.
2. A donation can help you to buy a cup of coffee (or tea), however, not replace your full-time job.
3. If we are talking about Github sponsors, the idea is really good, however, if you are located in one of the following countries https://github.com/sponsors#countries, which is not my case, and I think my country won't be supported in near future.
4. To be involved in OSS is not guarantee tons of interesting job offers. In most cases, a good LinkedIn profile can be much helpful than good Github profile, and yes - to have good Github profile need to make something important every day that others can see your involvement, which takes more your spare time instead of adding several motivation phrases to LinkedIn profile for HRs.
5. OSS is a community and that's mean an opportunity to meet some interesting people.