Sure thing! I haven't had any luck adding new accessories with content patcher, but replacing xnbs still works. If you're interested, I can show you the process I used to add them to the game
So the only way I was able to get it to work was with the old GetDressed mod, and the early versions of Kisekea, because these mods over rid the accessory count. I haven't tried with the latest version of Kisekea, but it may be something that needs to be re-implemented. Anyway, here's an example of the accessories I was able to get in game, I also included the templates I used to help make the accessories Hopefully this method still works, otherwise there will have to be a new SMAPI mod that overrides the limit on the number of accessories the game looks for. Sorry I can't be more help!