Recently I've been playing Gwent about 14 rounds win the most but some days I'm playing 10 - 13 rounds win. However, this took me like 1-2+ hour per day in order to get there.
May I ask how many games and how much time you are spending to play gwent daily?
After taking a couple of months off and dropping to rank 9, I am back playing roughly 4 or 5 matches a day at various times. Playing all modes, though I am not really enjoying Draft much because of the actual 'draft' process.
I probably average over 3 hours a day on Gwent related content, but relatively little of that is actually playing as I usually am too vulnerable to interruptions to able to finish games. Most of my time is either spent reading or posting on forums or on watching Gwent streams.
I'm retired so probably have more time on my hands than most. I've been playing Gwent for three years now and probably average two or three games per day. If I'm having a particularly bad time at Gwent I play less and if there's a seasonal I particularly like such as Patience is a Virtue I tend to play more.