We used an 046 with a 32” bar for years cutting cured yellow cedar and had no issues. Keep the chain sharp and adjust your rate of cut so you can keep the saw pretty wound up. Make sure the Oiler is maxed as others have said. If you are needing to push hard to get it to cut then stop and try to figure out the issue, it should cut with no more than moderate pressure needed.
Milling chains are typically at least semi-skip, ground at ~5* across the cutter, and usually have a shallower raker depth (.045 vs .060 IIRC). They make more of a dust than a chip and produce a smoother plank without as much wastage, narrows your kerf by about 3/32” which adds up on the amount of sawdust and gains you a bit if you are trying to cut thin boards.
Use wedges on longer cuts to keep pressure of the back side teeth, not sure if it really matters but I have always done it anyway.
Best cutting I ever did was a 4” thick x maximum width (~25”) yellow cedar slab ~40’ long. I’ll have to see if I can find the pictures.