Different companies have different requirements, but generally if you know a bit of SQL and a bit of Linux terminal commands you should be good. Maybe have a browse through a testing framework like Selenium, though frameworks would vary depending on what the company does, so don't fret too much about that.
LogSeq uses bullet points. Obsidian is just pure markdown
LogSeq is open source. Obsidian is closed source
LogSeq has a predefined structure to it (folders). Obsidian allows you to have whatever folders you want
Personally, I use LogSeq for my day to day work. Primarily because I prefer the bullet point approach when taking notes. But some people would prefer writing long continuous text with Obsidian.
So to each their own. If you're interested, try both (they're both using markdown, so you can transfer between the two). I went back and forth a few times before settling with LogSeq
You guys are finding spare hours!?