Good question.
Based on what I’ve been able to find (mix of online reviews and WAAAAYY too much time on geometrygeeks.bike), the Oiz, the Blur, the Scalpel, and the Epic all use the same frame for the XC and TR counterparts; it’s the fork’s axle-to-crown that changes the effective HTA. I believe that the XC Oiz has a 69 degree HTA, which is the same as the 2018-2021 Blur, the 2018-2020 Epic (actually this might be 69.5?), and a similar range for the Scalpels.
I haven’t decided if I’ll go new or used yet.
I also have a Fox Performance 34 SC 120mm that I can swap in to make any of the XC versions slacker - essentially creating my own TR version of an XC bike.
I’ve probably done too much research at this point; my spreadsheet calculates Lee McCormack’s RAD, and compares HTA, STA, ETT, chain stay, head tube length, and weights (with and without forks, with the ability to change fork selections to see how that impacts overall weight).
Currently leaning towards a 2018 or 2020 Blur - and while I’d prefer the TR version, I’d also be fine with the XC version (especially if it came with a dropper).