DiabyKungFu I agree that Partey is better defensively than Zinchenko. However, I don't think we should play both at the same time as fullbacks so then, assuming both are fit, you have to decide which one to play at full back.
I'd rather have Zinchenko in than Partey mostly because I think our more defensive options at RB (White/Tomiyasu) are better suited for the 3-2-5 we attack in as they then allow Saliba to occupy the central CB spot with Gabriel taking the LCB and White/Tomiyasu taking the RCB. When Partey is in at RB and inverting, it's harder for Saliba to slide into the central CB slot, which is his best fit IMO, unless you start White and Saliba at CB like we saw against Forest.
It seems like the tactics on Saturday were targetted at Forest since Arteta felt they would park the bus and wanted to attack with 6 so I doubt we see that too often, especially with Timber out long term. I would have loved to see both Timber and Zinchenko in with similar tactics but I'd be hesitant to try the same thing with Partey and Zinchenko, if that makes sense.