This question "what is best" cannot be answered in any meaningful manner.
A cursory glance of the issues easily lays out the fact that this is a multi-variable optimization problem with multiple local optima. So, it depends on what you want:
1. Well-funded operation with long history, big cap, plenty of liquid cash and low counterparty risk (in this regard)
2. Broker, broker + bank license or broker + bank license + clearinghouse all in one?
3. API/features
4. Efficiency, uptime/SLA, historical ability to execute, delays
5. Pricing structure
6. Markets and tradable assets availble
.... etc.
The RH/WSB fiasco outlined the probles with at least 1 & 2.
RH does at least some of it's own clearing, but it gave way too easily margin to idiots and clearly was not independent. The order came from above and they folded. Cross it off the list, or anybody with similar business model, dependencies and lack of own liquid capital and risk mangement. I doubt anybody here was using it anyway.
IBKR was a more interesting case. It doesn't do clearing, but it provides much better account protection, is fairly well funded and does much better risk management. But they also folded, prevented even buying of stocks. This is completely unacceptable. Off the list (and my current broker, btw).
But then what does one switch over to? That depends on the requirements. All brokers have their issues and the above list is just a start.
I've been looking at non-US brokers (Degiro, Plus500, etc) because much of the crap comes from US administration/rules, but the alternatives are just horrible in all regards. I wouldn't trust any of them with more than 10K of my own cash. They are just betting casinos with horrible software/APIs/support/risk management/market availability.
So what is one left with?
The older, bigger, more expensive, clunkier companies.
There's no free lunch here.
If anybody finds a good non-US international alternative for IBKR, please let us all know.