Video editing is resource intensive. Here, for years, VP ran tolerably on a system similar to yours.
Increasingly, projects began to incorporate HD or 4K files and or multiple effects. While VP caching has improved, proxy editing proved useful.
But is was a hardware update - both CPU and GPU in the gaming-capable category - that made a significant difference. Night and day.
Allow the green (caching) line above the timeline to complete before initiating preview operations.