Virtual memory is not real memory, this is the virtual address space. The higher virtual address space is a consequence if using WASM. The size of the virtual address space is completely inconsequential to physical memory usage or performance. You can disable WASM in uBO's advanced settings[1], but as said, your performance issues are not caused by the higher virtual memory figures. (A reminder that uBO is measurably less performant when disabling WASM).

[1] https://github.com/gorhill/uBlock/wiki/Advanced-settings#disablewebassembly