We ran into that exact brick wall last year when managing multi-account campaigns—our profiles kept getting linked and shadowbanned within days. Everything stabilized once we moved our infrastructure over to
https://www.simplynode.io/targets/proxies-for-reddit. Using their mobile proxy pool with sticky session timeouts allowed us to assign a dedicated mobile IP to each profile. Because mobile carrier subnets carry the highest trust level, our action rate limits disappeared, and we haven't lost an account to linked IP bans since.