It's definitely not cheap to replace the electronic suspension, but not as expensive as anything german will be. I just replaced the magneride front strut assemblies and rear air-assist shocks on my '17 Premier and with parts and labor it ended up something like $2200. ACDelco would be more expensive, but they were on backorder. You can add another $300 or more for GM brand.
That's one issue for the Magneride system, finding parts can be hard. The rears were on backorder when I went to buy them.
The air compressors don't typically go out for the air shocks, and the dealerships don't really see failed suspension control modules, either.
When it works, it's awesome. Its a controlled ride and I noticed it stiffens up around corners to aid in handling. Makes my Suburban handle like my previous '19 Impala.