NSW tenancy notice laws?

Anyone I know who has property in NSW and been in a similar situation know the rules around this?

lol you know how you hear of property investors going.....screw it all I'm going to sell and put the lot into equity shares where I don't have the headaches.....lol had one of those days today.

Summary of facts;

We have a small 2br investment property in Petersham, Sydney.
Been rented out by the same tenants for about 4 years.
In the past every time the lease ran out we would sign another 1 year lease which they signed before the old one ran out.
Their last lease ran out a few months ago and have been month to month since (which we knew about but as we were committing to a new IP and didn't want a potential "break period" happening when we didn't have the cash to have two empty apartments along with the big 30% upfront deposit we just paid we let is slide).

Now that the new IP is settled and a new tenant is installed we wanted to get the tenants in Petersham to "re-up" to a new 1 year lease.

We asked the PM to send the tenants a new 1 year lease.

The tenants have come back and said No they are not prepared to sign a new lease and want to stay on month to month and are probably moving out in the new year.


Here is where I need advice on.

I found out that the today that in order to give the tenants notice to cancel the month to month and get new tenants we need to give them 90 days notice.....fair enough, its long but to uproot and find a new place ok (though the irony that they can vacate with only 21 days notice is mildly amusing eg I have to give them 90 days but they only have to give us 21 days notice....hmmm).

Here is the kicker though....the moment we give them notice they can vacate eg 1 day or 89 days later with zero notice at all. Just drop the keys off at the office and say....please send us a refund check for the balance of our rent.

Once you give them their 90 days notice, they can leave at any time, leaving us scrambling to find replacement tenants.

Is this correct?

How can the NSW tenancy laws be so skewed towards tenants?

How if we give them 90 days notice can they then give zero notice?

How come if we give them 90 days notice don't they have to give us 21 back from when they find their new place?

Looking forward to feedback if any other NSW landlords have been in a similar situation.