That's interesting. I did a reply of the entire MCC before Infinite came out; Quick Resume worked perfectly for every game in the collection?
Judging by your comment, I am assuming that you played campaign only? If so, yes, Quick Resume works well with the campaign.
But as someone who cares little, if any, for campaign, QR ruins multiplayer. It disconnects you from the server, but doesn't tell you, so if you enter matchmaking, you will never enter a match, and never receive an error message.
On the HaloMCC subreddit, I see the same question posted over and over: "Is Halo MCC dead, I can never find a match". 90% of the time they are on a Series console, and QR is the culprit. So I preach to people to manually quit out MCC always.
Halo Infinite has a similar issue, and although I dislike its multiplayer and stopped playing months ago, at least it warns you. Halo 5 generally plays nice with QR, but I quit it out every time just in case, as I play it every night.