Website sporadically showing on google SERPs. It is there one second, gone the next - using the same search term

We recently did an overhaul of our website. Switched to squarespace from a different service. We are using the same domain name. After the rehaul, there were roughly 70 urls that we were no longer using so I used the url remove tool to remove them and each of them returns a 404 page. We also added around 50 new pages. I have submitted new sitemaps at several stages along the way and have asked for each page to be indexed.

Since doing that, some of our pages have very good placements on SERPs. However, when using the most important and commonly used search term for our industry and locality, our results are very sporadic. One hour we are in the top 20 results, the next we are no where within the top 100 results, using the exact same search term. We are in a very competitive field, so my expectations are tempered. Being in the top 20 results is okay for now, but to not even be in the top 100 is obviously concerning.

Like I said, some of our pages are the first or second result when you search for terms targeted by those pages.

We have no manual actions or security issues.

Hi, I'm also facing this issue.