Hello
Thanks for reading my bid,
I have experience with other freelancers who had similar issues, most of these issues were due to using MYSQL when running Magento,
I highly recommend and so do my customers now, to use MariaDB (MYsql Locks tables when reading information from them) which in return spikes CPU usage and makes page loads slow.
MariaDB does not lock entire table but only the row being read.
This is one of many optimizations that can be looked at.
Look forward to hearing from you soon!