In my opinion, you'l have a worse time trying to come off of Zoloft than you would Suboxone.
There could be interactions that could be unique to yourself that other people here aren't experiencing. Suboxone and Zoloft have very unique pharmacological profiles. Buprenorphine is a μ-opioid partial agonist, buprenorphine is also a κ-opioid antagonist (which expands the anti-anxiety profile of the drug), and buprenorphine is also a δ-opioid antagonist. Buprenorphine's main active metabolite, norbuprenorphine, is actually a full μ-opioid agonist, a full δ-opioid agonist, as well as a κ-opioid partial agonist.
Buprenorphine and norbuprenorphine also have an effect at the ORL-1 receptors; but I won't get into that.
However, as I have illustrated here, buprenorphine itself has varying degrees of effects at different dosages, as the different proportions of buprenorphine to norbuprenorphine will yield different results on the receptors (too much buprenorphine will prevent norbuprenorphine from working, but a sweet spot dosage of buprenorphine will be high enough to get full effects but not too high so as to leave plenty of open receptors for norbuprenorphine).
I believe when you get the sweet spot of buprenorphine, the δ/κ effects balance out with only slight κ antagonism (which reduces anxiety), while partially and fully activating the μ-opioid in an optimal fashoin.