Not fully using server resource but site was slow when having traffic

I have a laravel apps site that having alot of visitor recently and its become very slow and take too long to respond. This system was like ads serving apps that will call image or code form other domain and serving images there. Example like them will call a script from my side and I will return them a HTML code or image file to their site. And even i try with return empty value or empty page its also slow or take too long to respond. But i check from my WHM or cpanel. Its still have alot of free resource and cpu/memory was just use 2% between. Its not about bandwidth limit also, its got 8tb limit to go. and not about sql as well because its din't call anything from database. Only filesystem. like settings.txt. This was my domain name ad-loupe.com. and I found out if I access without https:// example like : https://ad-loupe.com - This load slow and below was my top result. Tasks: 444 total, 2 running, 442 sleeping, 0 stopped, 0 zombie %Cpu0 : 3.0 us, 0.3 sy, 0.0 ni, 96.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : 0.7 us, 0.0 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu2 : 4.7 us, 0.0 sy, 0.0 ni, 95.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu3 : 0.0 us, 0.3 sy, 0.0 ni, 99.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu4 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu5 : 7.0 us, 0.7 sy, 0.0 ni, 92.4 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu6 : 0.3 us, 0.0 sy, 0.0 ni, 99.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu7 : 0.0 us, 0.0 sy, 0.0 ni, 99.7 id, 0.3 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu8 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu9 : 2.0 us, 0.3 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu10 : 2.3 us, 0.0 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu11 : 2.3 us, 0.0 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu12 : 2.0 us, 0.3 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu13 : 2.3 us, 0.3 sy, 0.0 ni, 97.4 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu14 : 0.0 us, 0.0 sy, 0.0 ni, 99.7 id, 0.3 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu15 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 65701248 total, 61626280 free, 1981516 used, 2093452 buff/cache KiB Swap: 1046520 total, 1046520 free, 0 used. 63131372 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 24398 adloupe 20 0 318788 21960 2908 S 2.7 0.0 0:01.61 php-fpm 22725 adloupe 20 0 318852 22536 3372 S 2.3 0.0 0:12.56 php-fpm 23111 adloupe 20 0 318852 22524 3348 S 2.3 0.0 0:13.52 php-fpm 24017 adloupe 20 0 318788 22056 2996 S 2.3 0.0 0:06.43 php-fpm 24335 adloupe 20 0 318788 22056 2996 S 2.3 0.0 0:02.80 php-fpm 24399 adloupe 20 0 318788 21964 2912 S 2.3 0.0 0:01.56 php-fpm 22699 adloupe 20 0 318852 22612 3432 S 2.0 0.0 0:13.66 php-fpm 23368 adloupe 20 0 318852 22532 3380 S 2.0 0.0 0:12.20 php-fpm Please help me if needed any extra information can let me know. Thank.