Sounds like you might be confusing PR with this 3 star thingy. I am a HKPR, but never have had 3 stars on my HKID and will never get this under any circumstances (I am Australian with no family in HK and no links to HK at all except the fact I worked there for > 7 years). So in my case I need to visit once every 36 months to keep the PR.
It's possible due to COVID immigraiton might be a bit lenient in bending this rule, you are the first person I've read about with some evidence of this, but then you mentioned about the 3 stars which to me is Chinese nationals, these people don't need to visit every 36 months to keep PR and never did before or after COVID. So the quesition is more about those PR without the 3 star, are they able to keep PR even after not visiting for 36 months? Do you have the 3 star or not?