Everyone is different in how fast dependence builds, it depends on a bunch of factors. But you are in a different situation than someone who has never taken opioids before. People who have been dependent on opioids before will develop tolerance and dependence faster than someone who hasn't. And when you are currently physically dependent on opioids, if you switch to a new drug/plant that binds to those opioid receptors, you will get withdrawal symptoms if you stop abruptly regardless of how long you've used the new opioid. It's not like you can really just switch to a different opioid, use as much of it as you want for only for a short length of time and then stop it abruptly without withdrawals - everyone would be doing that otherwise. The main alkaloids in kratom are believed to bind to μ-opioid receptors, and buprenorphine is a partial μ-opioid agonist. They will have slightly different binding profiles and therefore likely have incomplete cross-tolerance and cross-dependence, but even if there was some precise time limit of developing dependance to kratom it's not like you can just take kratom for less than that time limit and then stop it and feel fine. The idea is to just use as little kratom as possible and taper off of it, just like you would if using a Suboxone taper to quit heroin. In addition, Suboxone withdrawal is generally long-lasting, you will likely have PAWS to deal with even if you can cover the acute withdrawal symptoms. I would try to use only the bare minimum of kratom needed to make your Sub withdrawals bearable and try to gradually reduce your dose.