Seriously?
Maybe you need to watch this clip from "Court Martial" to refresh your memory about there "was never really any indication that Kirk was anything other than a young hotshot captain" :
Or maybe all those episodes where Kirk succeeds where many other Captains, Commodores and Admirals have failed disastrously, leaving behind wrecked starships, dead crews, horribly messed up Human-Alien contact. And this willful denial of yours kind of crushes the credibility of the rest of your post.
I may have overstated it a tad, but the fact remains that while TOS is on we don't get the idea that Kirk is legendary. Exemplary? Of course. But as I said, the key difference is we get the idea that there may be many other captains of equal mettle out there having their own adventures.
I'm generally of the belief that when it comes to fiction, the size of the heroes and the size of the setting are basically inversely correlated. If you are trying to tell a rocking space opera and the same few characters continue to bump into one another across thousands of light years, it makes your setting seems small and tawdry. Modern day epic SF series get around this by having loads and loads of characters and multiple POV chapters - which only tend to link up by the climax of the story. However, this is much harder to pull off for reasons of casting and budget in filmed SF.
I agree, mainstream fiction puts extremely low stakes on a pedestal as a measure of "quality". But even as you note, science fiction often and repeatedly features stories with high stakes, because it's often not simply about regular people going about their regular lives. Science fiction is allowed to have Earth-shattering consequences by virtue of what ideas the genre *is expected to tackle* without being shat upon as being "pulp". You can feel free to rail against high stakes stories as being "lesser" than stories with low stakes, but IMO, that is just snobbery. A series of high stakes stories is no more "pulphouse" than a series of low stakes stories simply by virtue of the stakes. As an example, Spider:Master of Men novels often start with a drama level of about 9 and go up from there. That, IMO, is irrelevant to their quality, which is the author's ability to write, which is exceptional where it comes to in maintaining that dramatic level while still offering exceptional writing for the genre he is tackling.
I am a science fiction fan primarily because I enjoy the "sense of wonder" involved in the works. This doesn't have to mean high-stakes though. For example, as a child I loved the setting of Larry Niven's novel The Integral Trees - the idea of a human civilization in free-floating air. The plot itself however is a simple story of survival for a small band of nine people, nothing more or less. It's the setting that makes it stand out from mundane fiction - and the setting that makes it SF. Of course, Niven could have made the whole story about the potential destruction of the Smoke Ring and all human life, but he didn't.
Another great example is Frederik Pohl's Gateway. It was a fantastic novel which allowed many a daydream when I was a child. The stakes in the story however are fairly low. Robinette Broadhead isn't out to save the universe - he's just a poor guy from Earth looking for a lucky break. But it's easy to empathize with him - to put yourself in the mindset of going into an alien spacecraft without knowing what the hell you're doing, and seeing what happens.
Besides, there are copious examples across all Star Trek of truly abysmally realized low-stakes stories which profoundly demonstrates the fallacy of any claim that reducing the stakes of a Star Trek story makes it better by virtue of having lower stakes..
Some of my favorite episodes of Trek have low stakes:
(TOS)
Devil in the Dark - A single mining colony - and a single Horta - are at risk
Trouble with Tribbles - Who is at risk here exactly? I guess the colony that had its grain eaten
(TNG)
Measure of a Man - Just Data is at risk
Family - No stakes other than Picard's relationship with his family
The First Duty - Really, just Wesley's career is at risk
The Inner Light - No one is really at risk at all
Tapestry - Just Picard's future - apparently the world is fine if he doesn't become captain.
Lower Decks - Just one ensign's life
(DS9)
Duet - The life of one man hangs in the balance - that's it
House of Quark - Stakes are limited to Quark himself
The Visitor - It's all about Jake and Ben's relationship - Apparently the quadrant turns out better without The Sisko
In The Cards - Lighthearted comedy all about Jake and Nog trying to get a baseball card
Far Beyond the Stars - Stakes are Benny Russell's career/self respect
It's Only a Paper Moon - Stakes are whether Nog recovers from PTSD
I could go on and on. But the fact of the matter is a lot of great Trek episodes involve relatively low stakes beyond the personal level/the lives of one or two people. If you expand it to crises which threaten the ship/main characters alone, and don't have global implications, it probably includes most good Trek episodes.
And The only real difference in this area between Discovery and TOS in particular, or prior series of Star Trek, in general, is entirely structural. TOS is a series of discrete short stories, some of which are low stake some are high stakes. Discovery seasons are written like novels, where each episode is a chapter and the low stakes narratives they contain (of which there are many and often stretched out over multiple episodes, as in novels are stretched out over multiple chapters) are contained within the larger story..
IMHO the structure of Discovery - relatively tightly serialized within seasons, but loosely across them (because they are winging it) kinda hurts the show, because if you want a big epic story, it feels less artificial to let one slowly build over say five seasons (Babylon 5's original plan) than to try and come up with some entirely new high-stakes drama to push the show forward in each season.
PS, your denigration of comics as a literary art form is noted and rejected. Like any other literary art, there are many award-winning comics and otherwise which refute your notion that they are a lesser art form by virtue of being comics. Heck, there have been many exceptionally written Star Trek comics, for instance.
Not my jam, comics were my older brother's thing. I can only geek out on so many things at a time, and 90% of everything is crap after all.