Most of the time, bans happen because Reddit flags the account for policy violations. That could be from spamming, over-interacting, or your IP/device ending up on a blacklist. Honestly, I’m pretty wary of Reddit as well as Quora, so my advice is: when you create a new account, make sure to interact slowly at first. Read some posts and threads, leave a few comments, maybe upvote or downvote a bit, and only then start doing your main activities.
Also, use a good proxy source (usually static residential IPv4) together with an antidetect browser like GoLogin, Hidemyacc, Dolphin, etc. That way you can at least reduce the chance of getting banned because of your setup. But in the end it is still hit or miss. I have been banned before even when I did nothing wrong, and appeals almost never get the account back. Really frustrating.