Only thing shown in there was your 3 VMs using cpu. When you see spike CPU, run htop or top at the linux prompt to see what processes are using cpu.
top - 22:04:15 up 14 days, 8:08, 0 users, load average: 2.95, 3.79, 5.87
Tasks: 634 total, 2 running, 630 sleeping, 0 stopped, 2 zombie
%Cpu(s): 2.2 us, 2.8 sy, 0.0 ni, 95.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 32196.3 total, 2019.7 free, 26162.6 used, 4014.0 buff/cache
MiB Swap: 0.0 total, 0.0 free, 0.0 used. 4918.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
8316 root 20 0 9354092 8.1g 19204 S 82.4 25.7 14356:40 qemu-syst+
10128 root 20 0 9265796 8.2g 21072 R 76.5 26.2 12721:27 qemu-syst+
8745 root 20 0 5066388 4.2g 21120 S 35.3 13.5 8788:36 qemu-syst+
7679 root 20 0 6924 3264 2316 R 5.9 0.0 0:00.02 top