If budget is unlimited, our recommendation is always to keep a PR team on retainer, because a PR team will be able to support you with required brand storytelling that we cannot support, like fundraising announcements and product launches.
Stacker Studio can help with SEO in a way traditional PR cannot; the coverage and links from press releases via PR Newswire or other will not drive material SEO growth, and any manual outreach a PR team is doing to earn media mentions is valuable but not scalable.
In terms of budget allocation, you should prioritize investment in PR if your main content priority is supporting the announcements of fundraising, product launches, and branded storytelling/reach or niche outlet coverage; if your main content priority is organic growth through SEO with ancillary brand awareness/authority, then Stacker Studio should be your priority.