It’s funny you ask. I recently watched a YouTube video from Garden Answer of a renovation. I love her wall paint color & it seems close to what you describe. I’ll try to post a link below to the video. In that video at 23 minutes they discuss the beautiful greenish/grey/beige wall paint color Laura’s Mom chose. Mom says it’s a custom color but closest to Hardwick White by Farrow & Ball. (Color sample Link below) I made note of it because i like it that much! Is it what you had in mind? If so, the big paint stores (Sherwin Williams or Benjamin Moore) can color match to it. They have stored references for color mixing so id call them to ask if they have the one you want. otherwise, you may need to take in a sample for them to scan & analyze to match it. (No extra cost) I’ve used both SW & BM brands several times & I prefer BM. Although BM usually costs a bit more, it covers beautifully & it gives a better, more durable finish IMO. You'll probably only need a gallon or just a few so its worth it, right? Home depot Behr is ok if its not a room you really care about or your color is not too saturated (like i did a deep Burgundy once)
Paint:
Hardwick White No.5 | Handcrafted Paint | Farrow & Ball
Garden Answer YouTube video (@ 23 minutes)
https://youtu.be/cSxQGDYXWjs?si=3yP541H3ZGbrHXrx