ESXi host overall performs slow, you may see high ready value for system process in ESXTOP.
Slow boot process and restart happens during ESXi loading various module
This issue is seen with Intel hardware model S2600BPB with Xeon Gold 6100/5100, Silver 4100, Bronze 3100 (Skylake-SP) CPU Series.
To resolve this issue contact Intal for power supply issues listed as per https://www.intel.com/content/www/us/en/support/articles/000026748/server-products.html
Workaround is to Power Off ESXi host where removing power to the chassis for a minute and then re applying power and booting everything again.