That's totally fine because there is a build up. Have you seen the recent yaoi one's??? it's straight up smut which I enjoy but if Karas does that to Abel especially in that twink form right now, I would instantly drop it. It will be like every two other chapter would be Karas Graping Abel with Karas's personality. Regas is a perfect Shonen Ai. This is how a slow burn should be
I agree that this type of slow burn shounen-ai is nice sometimes, at least when the story itself is interesting. I also like "Turning" and "Death Delayed for a Short Time Because of the Will" for the same reason.
However I can't stand it when a story COULD be interesting but drags out waaaaay toooooo much and gets boring like "The Strange Story Of A Guy Next Door And A Novelist"
Links below if interested:
https://www.mangago.zone/read-manga/turning/
https://www.mangago.zone/read-manga/death_delayed_for_a_short_time_because_of_the_will/
https://www.mangago.zone/read-manga/the_strange_story_of_a_guy_next_door_and_a_novelist/
I'm not Shonen Ai person but Regas is worth the investment. Regas would drop it's charm if it got smut. Slow burn is what makes Regas interesting, personally for me. I'm a heavy Yaoi reader and I love this shonen ai story