There was really no one else for Suga to fight but Merab, everyone behind him was booked or coming off a loss and Merab had his 10-fight win streak plus beating Cejudo who had just lost the close decision to Aljo prior.
We had to wait 8 months after the Aljo fight (second round KO where he took no damage, though I know he said he had a rib injury) for the Vera rematch, then another 7 months for the Merab fight (didn't take much damage in the Vera fight except for the body shot at the very end of the fight). Saying he "immediately went for Merab" is definitely some hyperbole, he didn't duck him but he didn't rush to fight him ASAP either.
Woodley defended the belt 3 times in a year, Izzy defended the belt 3 times in a year, Poatan defended the belt 3 times in a year - a lot of these other champs are doing less then twice a year asking for 7-9+ months in between fights and are usually not getting surgery or anything that would justify such long layoffs.
I mean if we want to be honest about Suga he never deserved the title fight in the first place - he got gifted a decision against Yan to leap-frog him like 10 places up the rankings. Then they pressured Aljo to fight on short-notice with an injury in Boston of all places (Suga got a 10-month break from the Yan fight, Aljo got a 4 month break from Cejudo which was a 5 round fight), then he gets to fight a non-top 5 ranked Chito who was coming off a close decision win against Pedro Munhoz of all people (the guy who got a NC with Suga after winning the first round because of Suga eye-pokes).
It all really just leaves a bad taste in your mouth in hindsight - really shows you how the UFC loves to put their thumbs on the scale to manipulate the fight scenarios to the best of their abilities to heavily favor certain outcomes.