Error with key?

my log id: 0797dd5025a3145f7108781c

The site documentation gives no clue how to wrk with keys, when I try to log in through CLI, I get
ERROR Bad key found: no private key material or GPGKey
Logging in through web site works.
I see my key, ABCDEF1234567890 with "edit" next to it. Edit allows me to upload a new public key (it is updated elsewhere). FPR is unchanged. I provide my keybase passphrase.
Error: No signing key found

OK, so I don't have one, only a public key that was uploaded when I created this account long ago?
That must have worked once upon a time since I have verified myself on Twitter, Github, Bitcoin, Reddit, etc? Or do you not need to sign when verifying yourself on these?

So, how do I handle private keys on the website? Or signing keys? Or upload private keys, though I really am not too keen on that, no offense? The documentation gives no guidance whatsoever, and I find no link, no button, no menu choice that give me any clue how to proceed.

On my "personal page", I have a button "Action required":
Install Keybase (files waiting from xxxxx [unknown person])
Reset your keys & start from scratch
Edit your account/settings

I have installed the Keybase app three times now, no difference.
Start from scratch: I rather ditch keybase.io (while a good idea), and go back to clean PGP that I have used for almost 20 years.
Edit settings:
Change password: No thanks
Devices: If you install Keybase on any computers, those installs will show up here.
No device shown, restarted PC 4 times
the other three; not relevant, for the moment.

Start with the CLI login flow that reports “Bad key found” and “No signing key found,” then compare it with the website, personal page, and Keybase app key-management paths described here. Document how public and private signing keys are handled, including what users should do when only a public key exists; done means the relevant CLI and website steps are clear.