What's worrying is not just the existence of the NSL. Some people said it's only there as a warning and to deter people. That might be true, but the police almost randomly posts search notices for American citizens living in the US for violating the NSL. What is the point of this except pissing off the US?
Also, the recent rumors about a Corona/DNA screening of the entire HK population. I think especially many expats here would not be very pleased if this is happening. Same thing with the "mainland help", medics sent over and so on. The government has gone into overdrive. This has nothing to do with national security anymore. The only reason for politics to make all this noise now is either just to show their loyalty to Beijing or they actually believe that this kind of stuff works as propaganda to HK's society.
My hope for HK is: This political shitshow ends soon enough as the dust settles, and while the NSL is here to stay, public institutions and the society as a hole can then continue to exist at a much better functioning level than they do on the mainland. This means they talk of HK as part of China, but effectively internal governance is still at an acceptable level for international corporations and their employees. If they don't, and people in HK will be increasingly subject to random draconian measures, then I can only see international companies scale back a lot, which means it would be time for many of us to say goodbye.