I read this in high school, some time between 2018-2020. I believe there was something related to dragons in the title or cover art. The book was in English and I cannot remember any character names.
The main character was in his late teens and is raised by his grandfather/father who is a healer/herbalist. The character has a triangle mark(?) and he is supposedly the chosen one because his mark has all powers of the other marks (warrior, healer, and crafter).
The main character's father also had the triangle mark and was super distraught because his son had the mark as well which meant all that he did, did not resolve the big issue and he died shortly after that in battle. Both of the main character's parents are deceased.
Healers are able to heal wound by mending. They tend to be very sappy as the grandfather says, but when the main character heals someone he envisions it as mending a crack in a clay pot (wet clay) which combines his healer and crafter powers without him realizing. Crafter are able to manipulate materials when making something.
At some point a dragon lady (who can transform into a dragon) comes and finds him and they go off on an adventure to awaken his latent powers. In order to awaken his warrior talent, the dragon lady takes him to a village where he learns to fight, and during that time the main character and the dragon lady fall in love and I believe at some point they get married.
Also a big plot point in the series is when the main character frees a bunch of giants who were enslaved and they make him a bed. The giants did this as a way of showing thanks because they do not say thank you if they could repay the favor, and the main character had stood up for another giant and taken that giant's lashes for him, and when the lady transformed it was into a big dragon.
A scene I distinctly remember is the main character is doing work on a farming field and gets whipped by one of the slavers with a magic/enchanted whip, and instead of hurting him and cause him to feel slimy where the whip hit him. Also on another occasion when he was whipped with a whip that had sharp rocks on it, he was able to transform his back into stone to defend himself.
At one point the bad guy was able to corrupt another dragon that was sealed. This sealed dragon was called something along the lines of "the Black Dragon" and its human form was that of a 10-years-old child, roughly.