Hesitation

I mean ydi for wasting thier time

Why would you do something so stupid? You applied, which means either 1) your unhappy at your current job, or 2) the other job paid more, so why would you not take the job when offered?

YDI

Well, yeah. Duh. How did you not forsee that? They offered you a job, you said you want to wait to see if option B was a better deal, so they gave the job to some else who wanted it. It's not some crazy idea that you should be this shocked over.

You shouldn't have told them you have COVID

Never tell a prospective employer that you could do better somewhere else, accept the offer and then present it to your current employer to see if they can do better. Though they might be miffed at your lack of loyalty and sack you a few weeks down the track.

Well duh

BIRD IN THE HAND, dude. Seriously. If they thought you were eager to work for them, then you wouldn't be thinking about your current employer MAYBE offering more.

You should’ve just asked for some time to sleep on it. Never tell them you might get a better offer elsewhere.