Oh my lord , where to start !!?? Great minds think alike guys .... We must have all been typing at the same time
I'm presuming your set up and temps are correct .... I wouldn't consider assist feeding for a long while yet as there are so many better options IMHO.
First off l , I'd give her a 25 minute soak in a secure tub / rub in room temp water . I tried this a while back and my non- feeding Royal fed the next day ( she was a non feeder for 8 MONTHS !) . She also looked a hundred times better and much plumper so I think she may have been slightly dehydrated .
As she's probably distressed after being force-fed I'd leave her a week or 10 days before trying again . Are you warming the mouse /rat up before offering to the Royal ? Some will strike at it and others will only eat if you leave it in with them and leave them in peace for a few hours or even overnight . You can also try chicks or Multis as other options .
I'm sure others will offer some differing advice but that's what's worked for me in the past .