Hey there blueeyes and a belated welcome to the forums from all of us! Kratom (Mitragyna Speciosa) is a plant native to Southeast Asia that is, among other things, an Opioid agonist through its metabolite Mitragynine et al. It's use in traditional medicine in its traditional hearth region is well-documented, but only over the past decade or two has its use really gained popularity in "The West". For your purposes, the most important thing to know is that Kratom and its extracts will function in a similar fashion to the Oxycodone you're dependent upon.
On the potency spectrum, as it were, Kratom would be considered a relatively mild agonist that you could probably compare to Codeine. Be aware that it's not just an Opioid, per se, it also produces other effects which some have described as stimulant-like (not unlike Oxycodone, in that manner). Kratom has found popularity as a recreational drug, but also as an essential constituent of an Opioid-user's "toolkit", as in, it's an Opioid of lesser strength than say Morphine/Heroin, Oxycodone etc. and due to its dubious legality, can often be acquired through nominally licity means, although this is changing as we speak, so before trying to source any, make sure you can legally import it where you live.
I would suggest doing your own research on this drug. There's a lot to learn and as I mentioned, the situation is unfolding presently in regard to its legality.
You're right to be afraid of precipitated/induced withdrawal as a result of premature Buprenorphine initiation, but the good news, is that if you've already consumed your dose and feel better, you are almost certainly not going to experience any discomfort. Typically, there will not be a "feeling better" phase with Precipitated Withdrawal, you will just become very, very ill at a rapid pace.
If the Buprenorphine works for you and you have a reasonable means of acquiring it in the future, than I would say you don't need to go to the trouble of finding/acquiring Kratom at the moment, but as I said, do some research so when and if the time comes, you'll know what move to make. Let us know if you have any other questions, and again, welcome!