But it won't hurt :)
A thing that might be more productive would be to see what some of the core tech some jobs you are looking at use, and then re-implement that from scratch. You learn a lot, you can post that kind of stuff here and elsewhere and maybe be discoverable, and you can talk about it during an interview in a way that promotes you as an expert on something.
Where I work, once most of the candidates have been filtered out and there are only 1-5 remaining, managers get help from the senior engineers to assess the candidate's technical skills before interviewing. In my specific team we try to find code samples from github and contributions to open source communities (we love ohloh.net).
But we also do a "technical interview" with some fizzbuzz stuff. More than once we found candidates with good-looking open source patches but that couldn't implement fizzbuzz-like stuff on a whiteboard.
It did, however, differentiate me at interview time. I could demonstrate an ability to solve hard problems with original solutions in a way others could not. I could demonstrate product management like an expert where other developers where not even a beginner. A massive project like this really allowed me to utterly destroy the competition when trying to get that job, but only as I talked through the value of that experience.
Having this sort of experience also created some major frictions, though. You might look like a rock star during the interview but there is a huge difference between what they want in theory versus practice. If you are coming into an organization that isn’t as obsessed with product quality or user fulfillment as you they won’t care how good you are or how good the product could be. This is especially true of your developer peers who have never contributed to open source. Instead they will care only for the popular mediocre way of doing things that you have learned hard to abandon in search of quality and performance. Any attempt to raise the bar, increase developer performance, or execution speed with be met with disdain and immediate hostility.
After going through frictions like those for years I have learned to settle. I still hate giant frameworks and the billions of packages developers with hide behind to avoid writing code or learning anything works, but have learned to accept that nobody cares until the business is ready to fire people. I just wish developers would at the very least give two shits about writing some basic documentation but even that feels like asking for too much.
At the very minimum at least learn to write good documentation.
Considering the volume of similar bootcamp folks out there, I think it helped a great deal in that context.
Recruiters looked for fun more than anything else, but I don't think it made any impression on them / made any difference with recruiters.
BUT 20 years of experience, I'm not sure they'll care as much about something like a portfolio.
On the other hand it can't hurt and if you're going to do it for fun anyway, have at it ;)
With your existing experience, It is not required to have an online presence, but is nice.
Recruiters won't likely look, hiring managers may.
I highly suspect your ability to summarize your 20 years experience well in a 1 page document will matter a lot more. And you don't need a project to be on Github to be able to talk about it in interview.
That said, it's incredibly common for people to have a bunch of different things to showcase. You'll hear a lot of people who are "speaker, author, blogger, consultant" and still are just average skills with average salaries.
If you're going to do it anyway, go ahead and do it, but the return on investment is probably lower than just grinding Leetcode.