Personal: Choose FOSS first, and contribute some of your time and money towards projects that align with solarpunk ideals. Get into self-hosting and eventually perhaps community-hosting for local organizations or neighborhoods or someting like that. Find your local makerspace and meet up with tinkerers there and find common community projects to work on.
Work: At my work, my small team of devs are currently trying to break out of an otherwise heavily Microsoft-based ecosystem. So far we've gone from a general hostility towards FOSS to being allowed to run things on bare metal Linix servers instead of Azure, and I my request for a Linux laptop is approved (though still waiting on them to learn how to install Linux or something?). As part of a research project we are trying out FOSS alternatives to Microsoft products in hopes of creating interest and success stories. We are also in that project going to open source some of our internal development. I've also challenged my bosses on the heavy use of products from a single major tech company.
I have been a major sinner on the backup front, but I'm now in the process of setting up automated restic encrypted backups that first copies to a different hard drive, that is then is rscynced to my Hetzner storage box (you can also swap this around - rsync to another hard drive, then use restic to dump it on the Hetzner server, but I want the backups with multiple snapshots locally as well). Primarily for Docker container configs and data for now, but I will set up similar automation for dumping stuff from my laptop on my local server and then similarly push encrypted restic repos to Hetzner. Not set up RAID or a NAS or anything like that, but I will eventually build a NAS. I am forcing myself to write the scripts in bash as well to get some more experience with it - I usually default to Python for any scripting, but in this case I would almost only use subprocess.run anyway :)
ETA: The 1TB storage box is 4 EUR a month or something like this.