Safe automated/scheduled posting across Reddit, Pinterest, Substack, Medium - what actually works?

Trying to figure out the safest way to run scheduled/automated posting across Reddit, Pinterest, Substack, and Medium for a content marketing effort spread across multiple accounts over weeks - not trying to spam, just want it to not get flagged.

For Reddit specifically, I keep seeing warnings that official-API-based schedulers get shadowbanned faster than just posting manually through the app. Has anyone actually run multi-account Reddit distribution long-term without bans? What's a realistic karma/account-age bar before a scheduler is even safe to use?

For Pinterest, is Tailwind still the standard for bulk-pin scheduling in 2026, or has something better shown up?

For Substack/Medium, is there anything that does native cross-posting well while keeping canonical tags intact for SEO, versus just copy-pasting the article over?

Mostly looking for what combination of tools + account warm-up practices people are actually running month to month without accounts getting flagged. Real experience appreciated, not marketing pages.

You don't need the API for any of this, you just need a browser and some patience. I built a Reddit scheduler twice, first one three years ago using the official API and it lasted weeks before accounts started dropping like flies, second one recently that just controls Chrome directly and schedules browser actions like a normal user would do them, and it's been running clean for months now because Reddit can't tell the difference between my script clicking "post" and me clicking it half-asleep at 2am.