NPCs/townie in public venues

Background

It's been a while since I had a sim running a restaurant so I decided to give it a shot once again and I was confused that literally all the customers were elders(like 95%) and there're barely any young adults. Adult sims may still come once in a while but young adults usually only come with their official partner(for e.g Clara Bjergsen sometimes comes with sims other than Bjorn but Bella Goth never comes without Mortimer). So I can guarantee that single young adult like Candy Behr(my fav townie) won't come to my restaurant unless I make her someone else's girlfriend/wife.

Problem

I also notice that not only restaurants that are terrible at spawning sims, lounges and pools are also apparently a safe haven for elders and hell for young adults(children will come to pools but not young adult and teens oddly). Gyms spawning the same sim over and over and don't spawn sims with level 9+ fitness, even sims with active traits like Don, Becca and J will stop coming to gyms when their fitness hit lv 9. Romance festival barely spawns young adults(the game always spawns official couples in the festival but its almost always Adult couple like the Fengs, the Fyres etc but not Eric-Alice, Darrel-Emilia etc). Young adults with high level of painting skill can sometimes be spawned as painters or vendors but usually only 1-2 of them. I usually hopes that a celebrity shows up in these venues so that the game will spawn random sims as fans(sims spawned as fans are usually pretty random).

Exception

Sims with lv 10 fishing skill(including young adults) will still be spawned as random fisherman and sims with lv 10 dancing skill(including young adults) will still come to nightclubs. 

Question

Is there any mods that allow me to set the rules about spawning sims in certain venues(like increases the number of the visiting young adults or remove the fitness skill barrier for spawning sims in the gyms)? I used MCCC to set the elder to be 10% and Adult to be 20% of the whole population but nothing changes. 

Note

There are no young adults in the screenshots below, only 2 adults spawned in the restaurant full of elders. 2-3 sims of these elders are paparazzi(paparazzi always have kleptomaniac trait) so they constantly swipe things which is very irritating.