I had a similar situation to you about a year ago, utilising my US HO layout, in that I obtained a mixture of Roco, Piko and Fleischmann HO scale (albeit DR), and can assure you that they will not run on Peco Code 83 track, or to be more precise, Code 83 points!
Peco Code 100 points are not an issue, but the odd wagon still rides up over on Code 75 points.
I dont know about Tillig Code 83 track though, and I’m not sure how easily obtainable it is either.
Brian