i5 processor is your slowdown, upgrading that to an i7 (7700K) would give you better performance due to the hyper-threading. Unless your budget allows you to move up to a six or 8 core cpu. Also setting up your SSD's as follows can help:
Primary Drive - OS/Software (SSD) - Includes your operating system and the base Premier installation. An SSD is highly recommended as it will greatly improve how fast the OS and programs startup, but there is usually not much of a performance benefit to upgrade to a faster NVMe drive.
Secondary Drive - Project Files (SSD/M.2 NVMe) - If possible, it is a good idea to separate your project files and disk cache onto a secondary drive. For most users a standard SSD will work fine, but if you work with RAW footage there can be a large performance benefit to using a M.2 NVMe drive.
Optional Tertiary Drive - Dedicated Media Cache/Scratch (SSD/M.2 NVMe) - Using a dedicated SSD for your media cache and scratch files can at times improve performance when playing and scrubbing through compositions. Upgrading to an even faster NVMe drive can give some performance gains, but the difference is more pronounce in other applications like After Effects.