If you already have DVD Architect 7 - which is a standalone program - you can continue to use it using the same process in Vegas Pro 22 as was used in the earlier Vegas Pro version (i.e. render to a format compatible with DVDA's allowable import formats).
As you've probably now realised DVD Backup is presumably a physical backup disc of your purchase. It has nothing to do with DVD Architect.
As for using DVDA7 with VP22 that is an entirely separate matter and yes as Dexcon said above DVDA is a stand alone programme and you can use it with any video files, preferably compliant ones. I use it with VP21. It's a great programme but is several years old now and is only 32bit.
Thanks to both of you - I rushed when buying the upgrade and only briefly saw DVD. Installed DVD Architect. Not sure if it will ever be used. Most videos I make go to streaming online.