To be fair, Covid likely played a part in that long silence. I believe there was even a hiring freeze for a bit in spring. Not that it excuses bad behavior...
I had virtually the same experience in 2018. Gave me an offer for less than half I was currently making too.
It crushed me because I found a team that I was unbelievably excited to work with.
I should mention though that I did re-apply last year and they were much more prompt
If the recruiter replied and said as much I would have been ok with that. At least they were communicating. Plus covid didn’t effect the US big time until March. That’s all of Jan + Feb they had to let me know something was going on.