Works great, fast, clean, simple. Highly recommended.
Disjoint set of platforms from the ones you mention in your second sentence, though.
QuiteRSS (Win,Mac,Linux), RSSOwl (Win,Mac,Linux), RSS Guard (Win,Mac,Linux), Ravens.js (electron), TT-RSS (self-hosting), FreshRSS (self-hosting), LifeRea (Linux only), Arss (macOS).
If you are fine with self-hosting, then I recommend getting FreshRSS over TT-RSS and FreshRSS have support for RSS Bridge which will make FreshRSS a powerful tool. I prefers FreshRSS because I can set it up in my XAMP easily, TT-RSS moved to Docker only. Also FreshRSS provide their RSS feed API for other RSS software to hook into it. So you can use mobile app with FreshRSS feed directly to it.
Now if only I could find the perfect Android RSS client to talk to it. EasyRSS is the closest so far, but it has some bugs that occasionally annoy me.
I personally run tt-rss and I quite like it precisely because it's light, fast, has good keyboard shortcuts, and has a solid Android app.
I used to use Feedly and it's also an excellent option if you're not into hosting your own infrastructure.
[1]: https://feedbin.com/
There's a paid hosting version that's only $15/year.
There's little or no keyboard support at the moment, but if you're interested in helping to either develop or make some suggestions, I'd be up for improving it! Plugin: https://addons.mozilla.org/en-US/firefox/addon/brook-feed-re... Source: https://outgoing.prod.mozaws.net/v1/08a450f6d21388f6bfc51f2b...
I don't really like in-browser but could tolerate it if it could do all of the above
I use ReadKit on the Mac (has filters, but local to the client) and Reeder on iOS. I am using FeedWrangler as the back end; its filter language (at least as documented) is unfortunately inadequate for my needs. Otherwise it's been fine.
Unfortunately neither meet your Win/Linux requirement, but just pointing out there are some excellent options out there.