first i would fix major technical issues , then improve existing content and internal linking. Once the site is healthy,then invest in relevant backlinks if the niche is competitive.
Same process will be adopted in this case. I would start by investigating the indexing problems in GSC and then try to work on the pages that are currently receiving impressions.
for a start, I will index the page nd then move forward to select the pages which have some impressions instead of buying backlinks.
yep, i would go and look at Google Search Console and URL inspection to find out why the pages aren't getting indexed. Once they can crawl the right pages, then we work on the content and internal linking.
Indeed, however, I would first analyze the actual pages that outrank you before taking the plunge to get backlinks. At times, more targeted content and internal links can help you narrow the gap considerably without costing you much.
I alway start with GSC to address problems that could be affecting the indexing proces nd then move on to those page that are indexed. no use spending money on backlinks when content and basic stuff have not been sorted out yet.
Maybe first you fix the technical issues like meta Tittle, Description, relevant tags after fix this all then go for Backlinks
