Slow movers racking up aged inventory surcharges at FBA, how do you decide between removal and external warehousing services?

The aged inventory surcharges on my slower SKUs are getting genuinely ugly and I can’t figure out the right play here. Some of my products turn over every 30 to 45 days which is fine, but I have a handful that move at more like 90 to 120 days and amazon is punishing me for it. The fees start climbing after 180 days and by 270 days they’re painful enough to notice on my P&L. The obvious move is don’t send slow movers to FBA but these products sell consistently through amazon and prime eligibility matters for the buy box on my listings. Remove them and I lose prime and sales tank. So I’m in this weird spot where the products need to be at FBA for visibility but the storage economics make no sense for anything that doesn’t turn over quickly. Sending smaller quantities more frequently sounds like it solves the problem but the replenishment gap creates stockout risk, and running out of stock during a replenishment window means lost ranking that takes weeks to recover. External warehousing services with a drip feed approach keeps coming up when I read about this but I want to hear from people actually doing it before I commit to that workflow. If you have SKUs that sell consistently but not fast, how are you handling the storage fee situation without killing your prime eligibility?