I have the same problem right now like the OP. I am doing everything manually right now, I had 10 accounts active on Dolphin, I use 4 of them on daily basis combining regular activity with spamming, they're all working good for months. The rest 6 accounts are getting replaced as soon as one account is banned. They are relatively newer, all warmed up for a few days. In fact, I marked them with numbers, so accounts 1005, 1014, 1024 and 1027 are still working like a charm. Other accounts are banned in time, the latest account is 1060, but I managed to work with most of them at least for a few days. But lately I had trouble to log in with Dolphin having problems with reddit security. Eventually I managed to log in, but I believe all these accounts were flagged at that moment. Eventually 6-7 accounts were banned after my first regular post, some of them even after a few comments. Then I changed mobile to residential proxies, I also switched to AdsPower. Added 6 new accounts, 1 proxy for each account. I logged in without any problems, I warmed accounts for a few days but all the accounts were banned after the first regular post (no spam, no shit, regular content). The best thing is - those 4 accounts from the beginning are still working normally! So, what's the catch with this? I am using those 4 accounts the same way as others!
P.S.
It might be related to proxies as I am getting specific security errors with different proxy platforms I use and different type of proxies.