I have never met KT so cannot comment on the man. I don't even recall hearing him speak!
JFH took over Burton following Gary Rowett when they were in a good place and he only had to continue in the same vein to be a success. QPR was a different proposition, mid table effectively taking over from 'club wrecker' Harry Redknapp and after the initial new manager bounce he struggled to get the best from a squad who were in the PL the previous season and was sacked when 17th after 11 months in charge having had the benefit of two transfer windows. Not much to suggest that he has the experience for our current situation?
Obviously we all hope that they both have a successful time with us but..... from what I can see, taking off my claret spectacles, l struggle to be at all confident.
He took over Burton in the playoffs and went up as champions in League 2. Left them top of league 1 I think?
Qpr had Chris Ramsey and then Neil Warnock after Harry Redknapp. Was different from the premiership team having lost effectively their entire first team squad upon relegation (Since JFH, they are only 1 point above where JFH left them).
Besides that... you are right that he has never been involved in a real relegation scrap. But he currently does have his hands tied with such poor attacking options available to him. The ones who actually look like scoring are currently injured.