Is 8 GB RAM enough for a membership website?

I run a WordPress membership site with user accounts, restricted content and several plugins. Shared hosting has started to struggle when multiple users are active at the same time.

I’m planning to move to a VPS with 4 vCPUs, 8 GB RAM and NVMe storage. My budget is around $25–30 per month.

I’ve been looking at hostpro.com alongside other providers, but I’m unsure how much additional RAM a membership site actually needs compared with a regular WordPress blog.

Would 8 GB be a reasonable starting point, assuming caching and database queries are optimized?