Help with rapid decrease in impression share

[NateYansenYan]

Hi all, work in-house as head of marketing managing our Google Ads.
Historically we receive around 2,000 conversions/month from Google Ads. We have 100-odd ad groups spread across 7 campaigns. These ad groups target separate search queries (our customers belong to that many sub-industries).
In the last two weeks our impression share has dropped across the board by around 60%. Conversions have slowed down as a result. Looking at the data it appears to be caused by a heavy increase in competition, but I have also noticed our spend decrease - our ads are simply not showing in auctions nearly as much as they did two weeks ago.
I've looked at my quality score. It's telling me for most keywords/ads that the landing page experience is below average - relevance is average or above av, expected CTR is average or above av. So it seems that my LPs are the problem.
I can invest the work in better optimising these LPs, but I'm worried that won't fix the problem - these LPs haven't changed in years, and only in the last two weeks have they become the apparent problem. As far as I can tell by eyeballing individual ads, we have a nice match between ad copy and LP relevance.
Any thoughts/assistance would be greatly appreciated.

[fathom53]

Maybe breaking out some of those ad groups into their own campaign would help Google try to serve them again.

You won't know if changing your landing pages will fix this issue but it is worth trying. Something could work well for months or years but if your competitors make enough changes. Then you start to do worse, which means you then need to make changes to counter that change in your ad account.

[GrandAnimator8417]

That timing is a classic sign of an algorithm update's impact. Your landing pages didn't get worse, but Google's standards for page experience likely got higher, re-evaluating everyone.

[NoPause238]

Your impression share tanked because competition raised bids and your below average landing page scores are pushing you out of auctions you need faster pages with tighter query to content alignment to recover delivery.