The novel is good, yet it can be made even better.
Good Points:
(01) Writing is professional without grammatical mistakes.
(02) Character development is good, and they are interconnected with each other emotionally through various ways. Many characters have a back story, which helps to understand them better.
(03) Plot seems quite logical.
Bad Points:
(Please take this constructively)
(01) First and foremost, the Protagonist has no 'protagonist material', and if it weren't for you, the Author, pushing him up the ladder, I'm quite sure he would just be a random goblin.
You need to understand that a webnovel is based on OUR wish fulfillment, not YOURS! The audience needs the Protagonist to pursue wealth, women and power, which yours doesn't seem to be doing.
(02) Why did you make the Protagonist a transmigrator?
There are two major reasons why writers choose transmigrators as their Protagonists-
(i) So that the Protagonist has a different (modern) worldview than the native counterparts.
(ii) So that the Protagonist can have access to a cheat known as 'modern knowledge'.
Your Protagonist fails to achieve both. Being nice is not a modern worldview, and he does not show the shrewdness either which is found in modern society, which now makes use of diplomacy, or the so-called 'soft tactics' or schemes.
It felt very shameful that instead of the Protagonist, it was a common native goblin who invented the bomb.
What I want to say, is that your Protagonist fails to stand out! How can he build his nation by being naive? Instead, he would expect him to be more shrewd and a master of strategies, without sacrificing his good and approachable nature.
(03) It feels like you unnecessarily describe your novel to be more realistic! As I said before, this is a webnovel, and therefore, your Protagonist should be more glorious, even though a bit unrealistic. His adventures should be glorious to read, his romantic encounters exciting, and his battles thrilling...
(04) I just said his battles should be thrilling....
What does that mean?
It means that the Protagonist should have a cool yet ORIGINAL(SELF CREATED) fighting/battle/cultivation/magic technique.
(Of course it should have a cool name!)
Your protagonist seems very inactive with no signs of curiosity. He knows that he has turned from a human into a goblin, so why isn't he interested in knowing about the present world's supernatural powers?
Writers choose transmigrators as their Protagonists exactly for this reason! Modern people have exposure to a large number of fantasy sources.
If you argue here that he doesn't properly have his past life's memories, then it would be even more disappointing, because he cannot use his knowledge cheat when he needs it the most.
(05) Romance, Harem & Sex: If you are writing a goblin novel, these three things must definitely be included, or else the whole novel would feel obsolete.
What, don't like harem? Dude, that's a goblin! Plus, which ruler has only one partner?
(You can try a novel written by Goblin-Kun on Webnovel to understand what I'm trying to tell!)
(06) Governance & Socialization: We still don't exactly know how the tribe functions. What departments are under the tribe Chief?
Also, the Protagonist Sun didn't seem good at making decisions. When he became Chief, he set up an order for food distribution, and the male goblins were furious because he didn't force the widow goblins to be with the male goblins (or something like that.).
In such a situation, Sun remained passive as if the issue didn't exist. He could have encouraged the male goblins to court the widows by showing their worth, or by setting up a festival, etc.
Remember that such novels depend on three major things:
CREATION: Making all kinds of stuff like infrastructure, weaponry, medicine, etc.
MANAGEMENT: Finance, Military Tactics and Strategy, Farming, etc.
WARFARE:
(i) How the army is created and what weapons, mounts, formations, techniques they use, etc. (collective strength)
(ii) How do they differentiate against strength levels ? (like cultivation levels, or game levels, etc.) Fighting techniques, etc.
That's all.
Hope that you survive this criticism and continue to write this amazing work!!!