I think CBDs generally have tanked, due to work from home rather than any travel restrictions. Workers are the bulk of their denizens.
Not in the CBD it hasn’t. I’d suspect it’s the people digging stuff out of the ground that drove the economy.
In my experience, it was the resources construction boom that brought in so many ex-pats, which drove our real estate bubble and actual people visiting the CBD (almost 10 years ago now). With Chevron, Inpex, Shell building plants / preparing new projects; alongside the miners, every tier one, two and three consulting and services firm was opening offices and providing contractors to extract dollars above.
East/West/Central Perth apartments are still selling up to 25% below 2012-14 peaks, completely disconnected from the broader housing market. That's probably a lack of demand from ex-pats, international students and airbnb, which are all related to border closures.
The suburbs have always been a lot more exciting. Although when I first arrived into WA I remember going into the office on a Monday morning, mentioning I had found these fantastic Italian restaurant in Northbridge and pubs like Clancys in Fremantle, only to receive comments such as "...no one goes to Fremantle...".
Some things don't change

although we do go down to freo whenever
Escape hunt open a new room. After last years' first lockdown ended, we did just this, and tried to get a meal before doing the pub heist room. Walking up what used to be the 'cappucino strip' after dark, I was reminded why I don't go there.
Can you imagine walking down Hay Street Mall at 2AM on a Saturday night?
When in Perth for work trips we avoid the CBD once dark. And this is from years ago.
Never done it in over 60 years of living in Perth - so no. I am very out of touch with what happens at night in Perth CBD which is why I said "possibly". It is just that I always have a worry about some of the more sensational reports as 'bad news' seems to be what gets people reading papers or watching TV news.
I'd avoid Northbridge because it's not my type of crowd, unless I desperately wanted to try a new restaurant (Northbridge is busying up again for sure). But the main reason to avoid the CBD is there's not much to do there. Yes, some of the hotels have decent restaurants attached, and there are various other things dotted around the place, but without a significant resident population in apartment buildings etc, the city just isn't a convenient destination for locals. Kind of like Fremantle.