Now posting the third comment to hive. Looks like the Steem keychain by @aggroed, @yabapmatt and @stoodkev mixed in here before. It looked seemlessly working at login but did address steem and not hive. Fortunately Brave allows plug-ins to be set to a site by site mode individually. A Hive keychain is already there as well, however not installed here.

After adjusting this my first reblog did not work then, because hive.blog has somehow marked it as already reblogged even though it had been reblogged to Steem. Yet in the meantime I learned that peakd.com already does a very good job and reblogging then worked there.

Next thing is wallets. First I reached https://wallet.hive.blog/@andrepol with the server not responding (same as https://wallet.hive.blog/~witnesses) and still not responding. Now the wallet points to https://hive.io/wallets/@andrepol with access denied, while https://hive.io/wallets already shows plenty of options and again @andrepol/transfers is working seamlessly.

So here everyone has some first troubleshooting tips LOL