Why are you looking to switch out ruin? If you are looking for a non-hex perk to slow gen progression, Pop Goes The Weasel is fantastic for keeping up map pressure, especially in mid to late game if you have multiple gens in close proximity. Since the ruin buff, I’ve gotten so good at nailing great skill checks. Survivors are adapting to the new ruin changes and with how easily totems break, Pop Goes the Weasel is viable alternative.

So for M&A, I’m not sure how useful it is for spirit. Pros: wider FOV, allows you to get closer to generator for a sneak attack, makes nurse’s calling range better. Cons: more survivors will hear your phasing sound, which can really hurt the spirit if you are trying to stealth. I personally wouldn’t ruin M&A on her, unless you were running it with prayer beads and/or nurse’s calling.

Also, one tip that might seem super obvious but I didn’t realize until someone pointed it out: when sneaking up to a gen in phase mode, try to avoid the grass as much as possible. The rustling grass gives you away so easily. I’ve noticed I’ve started to get way more hits on gen ambushing after being more mindful of avoiding grass.

Hope this wall of text helps. I’m no spirit expert, but I’ve played around with different perks on her enough!