The NOD flag I found on Amazon and the GDI one I ended up finding on Etsy.
Nod Flag = https://smile.amazon.com/dp/B0817YWK4D/ref=cm_sw_r_cp_api_glt_i_XJMPCHSZCKXB5TYA4XSR
GDI Flag = https://www.etsy.com/listing/922803582/command-conquer-gdi-2nd-tiberium-wars?ref=shop_home_recs_2&sca=1&sts=1
I wish there was more official ones.
On amazon
https://www.amazon.com/dp/B0817YWK4D?psc=1&ref=ppx_yo2_dt_b_product_details
https://www.amazon.com/dp/B08T6NY2RD?psc=1&ref=ppx_yo2_dt_b_product_details