First off: "cleaning" the elements inside a cat should NEVER be necessary. If your engine is running properly, the OE cat should last the life of the vehicle. It's a passive unit, meaning it's functionality is directly related to the environment it's exposed to. That being said, aftermarket units are hit and miss.
Case study: my father purchased a brand new Hyundai Accent in 2018, the first year of the re-design. Within the first 5k miles it developed a misfire. Given the lack of sales of that particular model, and by extension the lack of sample size, the dealer was stumped. After multiple calls by the dealer to Hyundai corporate, it was discovered that engineering in Korea had identified that early engines were built with a bad batch of spark plugs early in the production run. The dealer replaced the plugs, and all seemed fine.
Around 30k, the car threw a P0420 code for cat efficiency. Obviously, it was covered under warranty, but it goes to show how quickly even the best OEM cat can be ruined by a poor running engine.
I've long touted the "Italian tune up" to my customers for this very reason. Many parts on modern automobiles work best when used to their full potential, and a convertor is no different. They require heat to function at their peak. I firmly believe that every car on the road would benefit from a weekly full-throttle on ramp run. Doing so allows the convertors to ignite, clears carbon, and heats the crankcase to a level which evaporates built up condensation.
Many of the issues I come across at the shop can be directly attributed to a given vehicle being "babied". Internal combustion engines do NOT respond well to repeated low load, low temp conditions. I sincerely believe my aggressive driving habits have a major influence over the fact that my 240K mile Jeep 4.7 use NO oil over the course of a 5k mile OCI. That's almost unheard of from that engine.
Load + heat = longevity.