Agree speech is not unlimited. Twitters gone way beyond that. With the president, trump never called on his supporters to seize the capitol or engage in violence. The argument is he incited them by falsely claiming the election was “stolen”. Further, if incitement is the same standard Twitter engaged in a double standard by not censoring several ds (including kamala harris) that egged on the spring rioters. If violence is the standard, they engaged in double standards with China Iran and their supporters. They further did not censor Antifa accounts in the spring actually calling people to violence
with the hunter biden stuff Twitter was later proven to be wrong so engaged in a fact Checking which was later found to be incorrect and thereby interferes with a democratic election
with respect to the mask/lockdown/vaccine stuff Twitter is now interfering in debate including among credentialed experts
as to the free speech argument, the difference between Twitter and say the gay wedding cake baker is that Twitter claims it is a content neutral platform that does not edit its content and therefore can’t be legally held accountable for the actions of posters. If true they have no business editing content except for the most extreme outlines you’ve given and which should be set out in law governing isps. If not, their immunity should be removed in which case they are free to speak but also bear the liability (like a magazine or newspaper).
I have no idea if what the tech companies are doing is the right move or not. What I do know is that these decisions they're making aren't being taken lightly. They have incredibly strong legal teams. I think they have a pretty good idea of what they're doing. For Twitter here's a more detailed explanation for suspending Trump:

I'm definitely conflicted on a lot of this. I think on one hand I totally get that many of these actions such as impeachment and social media banning will continue to churn the right wing propaganda machine, ultimately riling up the Trump base. On the other hand, Trump needs to be held accountable. We simply can't normalize his behavior. It's definitely a conundrum.