Go with Dulux Egyptian Cotton. At ΔE 0.7 from Balboa Mist it's essentially imperceptible — anything under 1 means the average eye can't tell them apart on the wall. Egyptian Cotton sits at LRV 64, a whisker under Balboa Mist's 65.5, so it reads as that same soft, warm greige — creamy when the light's warm, a touch stonier when it cools.
If you can't get Egyptian Cotton or you fancy a comparison, Dulux Weathered Pebble is your runner-up at ΔE 1.7, LRV 67.7. Still a very close match (anything under 2.5 is what we'd call very close), just a couple of points lighter and a more even-tempered neutral. Balboa Mist can go flat and stony in a cool north-facing room; Weathered Pebble holds its balance of grey and beige more steadily as the light changes, which can make it the safer call in a space that never sees direct sun.
The "but what about" here is sheen and base. Balboa Mist is a Benjamin Moore colour, and BM's paint has a particular soft, chalky depth that Dulux won't replicate exactly even at ΔE 0.7 — the pigment match is bang on, but the film and the way it scatters light differ slightly between brands. So if you're touching up an existing BM wall rather than starting fresh, a Dulux match will be close but not invisible across a whole wall. For a full repaint it's a non-issue.
Practical advice: order a sample pot of Egyptian Cotton and live with it on a couple of walls for a day or two before you commit a whole tin. Greiges like this are chameleons — they shift with your flooring, your skirting and the time of day. Paint a patch near the window and one in the darkest corner. If it stays warm and clean in both, you're sorted.