I renewed a few months ago. If you renew before your current application expires then you automatically get a 24 months extension.

As others have said you have to pay for a UK access code and US processing.

I was required to have a zoom interview which seems to be the hardest part as the zoom appointments have no logic ad to when they get loaded into the system. There’s a separate thread specifically on that I think. the interview took 2 minutes if that.