The Aurora's all come with a high angle stem already, and since it's one piece it's likely to be stronger. See this assembly video:
Evelo sells a Stem Extender (in the accessories section:
https://www.evelo.com/accessories/ ) for $29 (1&1/8" diameter, adds 3.25" of height), but you can find the same, or taller, on amazon:
https://www.amazon.com/s?k=bicycle+stem+extender&ref=nb_sb_noss_2
If reach is a problem as well, then a high angle extender might be want you want. Instead of the ZZTO I'd consider something like this:
https://www.amazon.com/gp/product/B00K3LQI84/ref=ox_sc_saved_title_9?smid=A1A7BS97M7Y0XY&psc=1
I'd want to be sure the easy adjustment locks down firmly, though.