I have a new server. I installed Magento 2.3.4 there. But the backend is so slow.
Hardware is:Intel Xeon E5-1650V22x SSD SATA 240 GB Datacenter4x RAM 16384 MB DDR3 ECC reg.
Plesk Obsidian 18.0.2 on Ubuntu 18.04.4 LTSPHP Version 7.2.30 FPM/FastCGI
I have already increased the RAM
I found this here but it is only with Nginx-only hosting. We currently only work in the backend. Frontend is not important for us