The FLs are comparable in both dramas (Thai ones are way stronger n fierce :P)
Both have similar MLs- Playboy, CEO, Cute gullible
Very similar to Thai series wrt- screen play n characters.
Classic 3 couplet story-line with well scripted sismance/ bromance/ and individual chemistry
The only Chinese drama with a Thai similar i've come across yet

Similar slow burn romance with a silent but caring ML
It has similar feel with one virtue per episode from each couple
Both are slice of life and light watch the chinese one has more romance

Both Ghost seeing Leads who solve one main story of the past
Kdrama GaDoShim has school setting and a very cute young cast (in fact all the other series of this FL are fantasy ghost genre) It will have a season two later

Either ML/ FL can see ghosts and together unfold a backstory/ suspense
Kdrama has Rich ML CEO while Thai one isn't
Rom com Fantasy genre

- Time travel
-Similar Medicine/ doctor kinda plots
-Strong FL in both with good comedy
-Kdrama has love triangle while Thai one has two standalone couples in diff timelines

Fl is older in both (Stronger in Thai one)
ML chases the female lead first
Childhood crushes
Superb playful chemistry between the leads
No annoying/evil/screaming characters rather good supporting cast in both
Both same duration ~32 hrs

Both ~10 years age gap and as per title the older FLs are quite rational
Strong hardworking FLs
The leads are great actors
Both First love (for ML :P)
Pestering moms in both (More so in Chugakusei Nikki)
Chinese one is definitely a lighter watch after Chugakusei Nikki

Both have Strong FLs driving madly towards their aim and a cute side couple
Both are office romance , Thai one is in Law firm and spends more time on the leads than Search WWW
Both are have a similar practical take on age gap relationships

Japanese-FL older than ML and reforms the delinquent Pink haired kid (amazing actor)
Higher age gap in the Japanese series
Both slight reverse harem
No villains all cute n romance

Similar Law based plot- I hear your voice is more thriller but the fantasy twist covers up for it
Both Noona romance with cute relatable chemistry
either one can lift you from a drama slump

Two couples with standalone stories of each
Very light Rom-com and pretty fast paced compared to Run-on
No excessive dramatics, no evil being (a rare for Lakorns i must say)
Well written characters not unique but act logically and not over the top
Character development

Same-
Office romance setting
older woman -younger guy
Fashion related content
Up until the first two episodes there's really not much difference in stage setting and storyline
I'd say watching either first is fine both are feel good rom-coms with ambition seeking FL n cute ML