On our Prusa MK3, our default starting print temperature with Matte is about 210-225.
On our Bambu X1, we print the Matte around 230-250.
Increase the retraction speed and distance.
Really make sure the first layer calibration is dialed-in. PETG is less forgiving than PLA. The Matte PETG is even less forgiving.
Reduce time filament spends 'idle' in the extruder.
We've noticed more reported issues with the Matte on prints with small details. Our thinking so far is that the when there is a slow rate of filament flowing the extra time in the extruder can cause it to jam. Increasing the retraction distance can help with this.
Counterintuitively, increasing print speed can help.
We will continue to compliment and amend this post as we learn more from our use and hear from our customers. If you have more insights about printing with our Matte PETG, please comment below. We will incorporate consensus findings into this post.