Do "breakup emails" actually work, or are they just a fast track to the spam box?

Before hitting the final delete button on subscribers who haven't opened an email in 90 days, standard playbook advice says to run a "re-engagement campaign." You know the type: "Are we breaking up?" or "Is this goodbye?"

But here is the reality we noticed: every time we send these win-back sequences to super cold leads, the conversion rate is abysmally low (under 1%). Worse yet, it often triggers high spam complaints from people who completely forgot they ever signed up, doing more damage to our domain right before we clean it.

For those of you who clean lists regularly: do you give inactive contacts one last chance with a clever win-back sequence, or do you skip the drama and just hard-prune them with zero warning? What has yielded better long-term results for you?