Yep, should be a driveside gap which you shouldn’t try to take up by packing with spacers or you wreck bearing life. The wave washer is very much a thing and isn’t always present. If you don’t have one it’s worth getting. Do make sure the dustshields are on properly.
It does look like this one might be a bit excessive though – can’t quite make out with the grease.
It’s typical SRAM I think, they always seem to find ways things need to be installed that are different than Shimano and that’s where a lot of the problems come from.
Regards nothing holding driveside in place – it’s just that the whole approach to preloading and retaining is totally different to Shimano. Properly torqued, it’s not going anywhere… 😀