All major browsers newest versions support the inset css property. My team is using princexml to create PDF’s from HTML and we are using a modern front-end framework, Angular, to build this HTML.
Because we only support always the latest 2 versions of the major browsers, the properties top, bottom, left, right started being converted to the inset property recently.
The problem is princexml throws a warning: unsupported properties: inset, and the design of the PDF actually looks totally wrong because of this.
I’m wondering if inset is going to be supported in a not so distant future?

We're seeing this issue too. We render our documents in the browser before sending the rendered HTML to PrinceXML. There is a Chrome "quirk" whereby inline top/right/bottom/left style properties are converted to inset.

https://stackoverflow.com/questions/65899348/prevent-chrome-browser-from-converting-position-property-to-inset

^ This thread covers the quirk, with a (very rough) solution

We too would like to see this feature in PrinceXML

We have added support for the inset shorthand property to the latest build, I hope that helps.