Isn't most produced output at work company confidential? A financial analyst won't open books to a new company during an interview. A devops person won't draw complete architecture diagrams either. Personally I don't understand why the web industry seems to think one has to do extra work on evenings and weekends (hobby projects) to be presentable. When somebody tells me they work on an internal tool or intranet of a large company I have to take their word for it, no way they can show me screenshots. At best I'd get a list of technologies used and can ask generic questions about those.

I'm grateful that some companies still offer technical tests and whiteboarding.

Had a mini heart attack everytime I see companies requiring significant open-source contribution.

The horror to imagine in the future when I decide to switch company, I won't be able to because of zero non-scribble repository in my github account.

It most likely depends on the company, too. Big and immensely popular companies might have that as a criteria to filter out all but the very best talent, but smaller yet still great companies might give you a chance if you present yourself as a talented and problem solving type of developer.

Not really dude, just list your experience and in the interview they will talk about it so you can elaborate on it.

What is your stack?

I cut my teeth on C# but switched over to MERN a few years back, and use WebGL for more CPU intensive visual stuff.

You should be good showing off a few websites made by you plus showing off your knowledge where you can, using technical terms and doing tests etc.