Looking for a wireless keyboard that operates with a 2.4 GHz USB dongle - something like a Logitech Unifying/Bolt receiver.
Not a necessity, but could be mechanical or bluetooth-enabled.
Would also appreciate tips on online deals (to buy new). Budget - something under 5k.
The budget is good enough to cover all your requirements. You can check some popular options above.
https://www.reddit.com/r/mkindia/
Use this subReddit for reference as it covers popular choices.
Have ordered a MX mini mechanical with help from @TheD4ddy
Needed something no-frills and durable, and with a smallish footprint, for work. Hopefully this should be a decent fit.