did a quick test, looping random note events across random vital presets in 5 instances of vital at the same time and the cpu meter in Renoise doesn’t go beyond 8.9% (AMD Ryzen 7 7700 8-Core Processor 3.80 GHz, ram = 32 gb). Perhaps it is a combo with other plugins that is causing problems on your end?
Also have you ever tinkered around with the settings here for plugins?
Having auto suspend on for certain plugins have caused problems for me in the past.