For a cat on its second or third blockage, usually yes: PU surgery, at roughly $5,000 to $8,000 with one Sydney specialist centre publishing $6,500 fixed, ends the blocking emergencies permanently in the large majority of cats. Each blockage episode costs $1,500 to $4,000 anyway, is genuinely life threatening, and the maths as well as the medicine start favouring the definitive fix.
What PU actually does: it widens the narrow end of the urethra where crystals and plugs lodge, removing the anatomical bottleneck. The trade is a modestly higher lifetime risk of urinary infections, monitored with occasional urine checks. Cats live entirely normal lives afterwards.
For a first time blocker, PU is usually premature: unblocking plus the boring preventives, wet food, water stations, urinary diets, prevents recurrence in many cats. The decision point is the pattern. A first episode is bad luck; a second is a trend; a third with the same setup is an anatomy problem asking for the anatomical fix.
Send what your vet said and quoted. A veterinary surgeon reads it and comes back to you with what they can do and what it would cost, before you pay anything. A written second opinion is from $250.
Send the case, hear back from a surgeon with what they can do and what it costs, and only pay if you go ahead.