Reddit can restore your deleted posts. However, if people flood them with GDPR / CCPA delete requests, they may become liable for lawsuits if they don’t comply.
It sounds like their current policy is to not delete your posts even when deleting your account, but there may be grounds for legal action here.
Reddit’s Privacy Policy and User Agreement apply to you either way, so I’d assume you’d be able to make a request based on that. Due to the EU’s GDPR regulations, most companies make their policies GDPR-compliant, meaning fewer variations, less work, and better consumer protections.