To give you an idea without getting into too much detail, a friend of mine involved in a small corporate lawsuit in the US that is easily already over $5 million per side in legal costs, and it's a completely run-of-the mill issue; we're talking two lawyers on each side. It's entirely conceivable by the end of it the winning party will have spent more money on lawyers than they will potentially get back. And then once that is over, there is a high likelihood the losing party will appeal, costing a couple million more.
Apple's lawyers are absolutely more expensive than the ones in the lawsuit my friend is involved in. And then there's the staff time spent dealing with discovery. (Imagine you are an engineer working on Siri and get an email from your boss "we need copies of any email or iMessage you sent from 2014-2024 regarding Siri. Oh, and copies of any notes you took at any meeting about Siri." All the time you're dealing with that you're not working. Then there is the staff time for those people to get deposed (which involves hours of lawyer and staff time to prepare for); for Apple leadership to get deposed (same preparation required), etc.
And yes, if Apple were to prevail, they could conceivably get their money back, but 1) it's not guaranteed 2) they wouldn't get staff time responding to discovery/preparing for depositions back, and 3) as
@ChrisA pointed out, there are potential unknown issues (what if during discovery it becomes apparent that one third-party contractor did record and emailed it to his personal email - Apple had no idea but now they're liable. Or a Siri engineer said "you know, we should send Siri requests to google - maybe they'll pay us another $20 billion" as a joke but it's not interpreted as one. Then the inevitable appeal of whichever side loses.
I am confident Apple was not doing what they were accused of doing, but I am also confident that for Apple to accept the repetitional hit that they are taking by settling on this, they are convinced the cost to defend themselves is orders of magnitude higher than $95 million.