I work as Software Project Manager, I was working in Big company (let's call it X) managing projects with around 10-15 SW developers working on them. I got contacted by a Head Hunter from another company offering quite a better salary and benefits, and told me the scope of work is similar or even more challenging. My notice period was 6 months which is long, they were willing to wait for me. Now, I moved to the new comppany (let's call it Y), people are very nice and friendly, but in the first 2-3 weeks I was schocked with the lack of work and the small scope. Here they have 2 developers per each Software Project Manager, beside everyone is relaxed and it seems the workload is low !! This low ratio of developers to Project Managers is the Biggest problem for me. Because I can accept that my scope now is small because I am still new here, but with this ratio, I do not see opportunity for my scope to grow. And frankly I do not think they need this many project managers !!
Another small company (Z) had offered me a job with similar high salary around 4 months ago and I declined, so I contacted them and asked if they were still interested, they said Yes and assured me that my work with them will be challenging.
So now I need to write my resignation, I do not want to make enemies in my industry, and I do not want to be blacklisted. My initial idea is to say the truth, but I am concerned that this truth will be an attack against my top managers in company Y who offered me a job without planning it correctly and were not honest or clear with me in the interview.
What do you advise me to say as reason for my resignation after one month?