URGENT: Why is my Amazon PPC Campaign ROAS CRASHING Despite All My Optimization Efforts?!

I'm completely stuck and tearing my hair out trying to figure out why my Amazon PPC campaigns are suddenly performing so poorly. I've been trying to fix this for hours and I feel like I'm hitting a brick wall.

• Context: I launched a new product line on Amazon about three months ago. Initially, my PPC campaigns were performing decently, showing a healthy ROAS and ACOS. However, for the past week, my ROAS has completely tanked, and I can't pinpoint why.
• Problem: My ACOS has skyrocketed across the board, and ROAS is abysmal across all my Sponsored Products campaigns, even those that were previously highly profitable. Sales volume is dropping fast, and it's becoming a major concern for this new line.
• What I've tried:
  • Lowered bids on underperforming keywords that were draining budget.
  • Paused irrelevant search terms identified in the search term reports.
  • Briefly increased bids on high-converting keywords to see if it helped, but reverted quickly when ACOS worsened further.
  • Checked budget limits multiple times – that's definitely not the issue, as campaigns are still spending.
  • Reviewed product listings meticulously for any recent changes or suppressed issues (there are none).
  • Analyzed search term reports for new negative keyword opportunities, adding several.
• Specific Ask: What on earth am I missing here? Are there any advanced troubleshooting steps or common pitfalls I should be looking for when Amazon PPC campaigns suddenly go south like this? Could it be a hidden algorithmic change that I'm unaware of, or am I just blind to something incredibly obvious? Any insights would be a lifesaver right now.

Thanks in advance!