I don't think OP's lying....or actually actually misplaced the bag at reception, instead of inside the room. Nor do I think the hotel was trying to 'attempt theft"

Do answer some of your question above...there's a few possible explanations:

1) Handbag was found by Staff A, before Staff B starts cleaning your room.
-> Staff A took it to the cleaner's room / lost & found...wherever they put it
-> Staff A forgot to log about it....resume her cleaning job at other rooms
-> Staff B cleaned your room, and legit never saw your bag...

2) Friday evening, they did found your bag after you left.
-> They decided it wouldn't be appropriate to call you "late" at 10-11pm.
-> The staff/manager that found it is off shift for the day...and decide to leave it to the next manager on duty to take care of it.
-> Lack of log / documentation
-> The next staff/manager that handles it.....does not know much about it
-> Lack of bag's identity**(see below)

3) When the police called the hotel on Sunday......do you know what kind of or which "manager" they were talking to? In any given hotels, there's at least half a dozens of "managers".
- It's not that surprising that the "manager" that picked up the phone doesn't know anything about it immediately when he picked up the call.....until he looked further into it.
- Not every hotel might have a formal (or actually follow the) procedure of logging lost items.
- If the cleaning lady really tried to attempt theft your wife's handbag....did you think the whole hotel's managerss would ally with her....and lie to you saying they never found it?? The risk of whole hotel's/brand's reputation for a few thousand $ worth of a handbag??

But I do agree.....there's poor level of customer service at this hotel. They didn't proactively tried to help you find the bag, nor did they try to proactively contact you when found it immediately.
However, that said, neither did the customer (you and your wife) tried to proactively help.
- It was 200km away, but why didn't you call the hotel / front desk immediately when you notice it was gone?
- Instead of relying on your membership/reservation details, why didn't you proactively leave your contact details with the hotel/manager on Friday afternoon when they can't find it? Sure, that would speed up the process and be able to contact you guys faster. Or leave other front line / manager on duty wonder what's this # / special note doing at front desk...

At the end of the day, both side of the party failed to actively search for the bag. But at least...it's now found, with all the items inside safely recovered.