I don't buy that HK's covid situation or divergence would trouble Xi's election at all. Changing tack here would not bring the much feared 'instability' if done gradually and messaged as a pilot. They simply need to make the vaccine pass rules from 24 Feb a de facto mandate and get jabs into the oldies fast.
It is also really not clear to me what it has to do with the Olympics over a thousand miles away, but the games will be over long before the wheels of HK policy move significantly anyway.
So that would be the sensible path. The only plausible alternative is to go "Full Xian", total lockdown and mobilise PLA or other resources from over the border and test the whole population 2 or 3 times in the space of a week to find all cases and lock them up somewhere. If they are going to make that call they have to make it happen in the next 10 days otherwise the case numbers will make detention implausible.