One of my clients has a website that is visited by tens of thousands of users per day. Google Search Console is showing continuous decrease in search impressions starting from 01-April-2018. The search impressions have decreased around 70% since then. I understand this is normal for the websites to have ups and downs in search impressions due to change in their ranking in search engines and also due to changes in search engine algorithms. But the confusing factor is that there is almost no change in search positions; rather they have improved a bit in this period. Similarly, CTR has also improved.
My question: how is it possible to have dropping search impressions (and traffic as also shown in Google Analytics) while there is a positive change in search positions / ranking and CTR?
Please note that this website is in a niche where there is no significant impact on search impressions (and traffic) by the factors like seasons, months, events, etc. as observed by us in the last six years.