https://nitter.poast.org/ianwcrosby/status/18727242319993817...
More about nitter: https://github.com/zedeus/nitter
"Guest accounts" were accounts you could generate to access Twitter without actually signing up, but then Elon Musk killed them so then Nitter was basically declared dead because most people don't want to spend time making tons of actual accounts to run a Nitter instance and then Elon Musk also made the ratelimits stricter so you needed even more accounts.
Some of the bigger Nitter instances used thousands of guest accounts.
So, speaking as a former customer, the tragedy and timeline you mention pass the sniff test for me. So glad your next venture has been going well for you!
However I can, albeit anecdotally from my perspective, say that I felt there was a marked difference in Bench's quality/service/responsiveness/performance/etc about 3yrs ago. This aligns with the timeline given by the former CEO in his post for his departure.