They probably sold you the bike because you were looking at a cheap bike and the Giant Cypress is a cheap bike. They may have recommended new wheels, I certainly would but they may not have because again cheap bike. A lot of folks aren't going to try and sell something that will cost money to someone not looking to spend much money. The shop probably is not at fault here. Most shops wouldn't have many if any bikes for really big and tall folks unless that is something they specialized in.

As people have said a handbuilt wheel by a professional with quality parts is more likely to support your weight than a cheaper machine built wheel that comes stock on a low cost bike. Typically a handbuilt wheel shouldn't break spokes unless a severe accident has happened and shouldn't need much if any truing. However any wheel will probably need a lot of adjustment if you are jumping off of curbs as a heavier weight rider. Wheels that see bigger hits especially on harder surfaces are going to have more issues than if you rode more sensibly and heavier riders put more strain on the system.

If you do break a spoke or multiple spokes and ride like that you will have very big problems like you did. The wheel true a year ago didn't cause the issue, riding on broken spokes did. Also shifting poorly can cause issues and one a commuter bike that is quite common. Commuting tends to take a harder toll on the bikes and without regular maintenance every six months or sooner especially on the cheaper bikes, they can see all sorts of issues.

If you are in the market for a new bike I would check out ZinnCycles or DirtySixer they both specialize in bikes for bigger and taller riders. If you are interested in keeping your current bike I would reach out to Bill Mould and have him build you a set of wheels. He built up my touring bike wheels and they have been fantastic.

In a new bike I would ideally look at a bike with thru-axles and hydraulic disc brakes on a good expedition level touring frame. I know for sure I would want the handbuilt wheels probably on something like the DT Swiss Hybrid 350 hubs or White Industries XMR hubs with DT Swiss Alpine III or Sapim Strong spokes and Locking brass nipples laced to 36h Velocity Atlas, NoBS or Dyad or Sun Single Rhynolite XLs Rims. The reason for all that is strength and reliability but also versatility.