You can unless they patched that, I was able to use one for one of the times they had that emblem sacrifice
Ah I see you don’t like the game content.
I wasn’t able to swap this challenge out. And before then I wasn’t able to swap out the challenge for the splatter backdrop, so it must have been patched.
Wouldn’t be surprised of it was a mistake on their end because this was prior to the big team.battle fix as well.
Makes you wonder if the ability to swap the challenge is there much like cross core customization but the Devs purposely locked us out of that feature.
Not kidding, glad I deinstalled. Made some grinds for other challenges tho. I feel you.
I endup completing terminals in campaing
Turned on the game last night… forgot the weekly challenge had been reset, as I’d long given up retrying to unlock it, let alone beat it 
I quit trying after 27 matches, only 1 of 3 CTF won, 24 other were any other gametype, this covers the initial posted statistics. Just anoying to get forced to play thru the list and fingers crossed you got a CTF and team mates on a close server that can handle the random competition.
Seriosely, I would pay for it not seeing on UI any stuff related to challenges, post game xp and shop advertisments. Halo 1 did not had it and went well with it. It should be completely optional to see this kind of stuff. I propably would not care if losing if I dont see everytime how bad I and the random team mates sucked at some games.
I propably would not stop trying if we were able to select the playlist for CTF. It propably would just took 6 matches assuming that the 50% win chance I end up with is set in place in the match making algorithm for everyone.
I’ve had the battle pass completed for a while now. Looked at my challenges last week, then looked at how far I had to go, didn’t even really try last week.