Expected CTR

Hello all,

I am researching ways to improve our Quality Score for our keywords.
The Ad Relevancy is ‘Above Average’ and the Landing Page experience is ‘Average’, though we’re still working on improving it.

However, the Expected CTR is ‘Below Average’.

Annoyingly, I can’t find a whole lot about it online.
From what I understand, its a mix of historic CTR, competitors CTR for similar keywords and search terms that exactly match your keywords?

Do I have that right?
And does anyone know of any ways to improve their Expected CTR?
I really think it is the biggest obstacle we have to get a better Quality Score.

Thanks in advance!