A catch-22. You can only submit a new Trek idea if you're established in existing Trek. Everything else won't even be read.
There are numerous "original" works that live from the popularity of existing franchises. Fanboys, Galaxy Quest, The Orville. A story "about" or a story "paying homage" to something still grabs off attention it wouldn't have received otherwise.
And dilution... what exactly is dilution. I guess some said TNG, DS9 and BOY diluted the original brand. Well, officially it was then called Franchise Fatigue. Or DISCO, Picard, Lower Decks, etc. juxtaposed Abramstrek with its timelines and stories all over the place. It's about money and control. Dilution is an excuse.
"Dilution" = metaphor for adding to an existing brand formula which, by accident or intent, reduces the brand's efficacy. DS9 definitely changed the format but created extended life. The 1996 movie First Contact added to the Borg, diluting its original concept - albeit gaining a little bit of life in the process. This is inevitable - universe building where the universe is set to a certain extent but then said building creates a wall that has to be gotten around. The more the wall exists only compounds the problem.
"Franchise fatigue" = continuing the saga for so long that it feels like everyone's walking the motions, painting by numbers, nothing new is being added, and it all feels monotone and stale. It's also why TNG ended a year earlier, as even in 1994 a lot of people were saying the show had lost steam (got fatigued.) Or earlier, especially regarding the music.
Depending on fan, what they've seen and invested themselves in, and so on, YMMV with the perception behind these conditions.
"Orville" et al took an existing trope and innovated on it with fresh ideas. No Trek franchise did a 2D episode, play around on a high gravity planet, or other sci-fi trappings. Orville's most derivative episode might be season 1's finale, if not the "we all live in a yellow asteroid" episode but even the asteroid episode had enough of a twist... Nor did any Trek do anything like "Majority Rule", which feels more like a "Sliders" episode and the influence of that show can be seen in other episodes, never mind people claim Sliders was homage to Quantum Leap, which is homage to Doctor Who, and so on and so forth ad nauseum.
"Star Wars" is old kiddie good-vs-evil mixed with swordfighting with Samurai influence with day-glo sabers and larger-than-life ships, proving - as Star Trek did with wagon trains westerns and shows like "Days of our Lives" - took from other genres outright.
Or the human being - we all have the same organs but depending on individual nuances to biochemistry, time of living, and other factors, there are plenty of differences that vary from person to person. Just like the taste of Soylent Green... metaphors rule and suck at the same time, just like ambivalence...
And there's another tropey term afoot:
"Rubbish" - throwing anything against a wall to see what might stick, turning the audience into a beta tester if not outright trolling. Early TNG did this. Early DS9 did it to a lesser extent. Often coupled with extravagant special effects in an attempt to hide a rubbish plot. TNG and DSC both did this in spades, especially early on. TOS had no extravagant effects budget, but the storylines were novel for the time as well as being more adult than juvenile (see "Lost in Space" as an example, noting "adult" and "juvenile" also have more to do than just target demographic.)