Here's the bigger issue to me.  Let's say you're 100% right about the conundrum where interpretations can be wild so we must look to Tradition in the form of various sorts like Church Fathers, supposed traditions handed down by the Apostles, etc etc.  If that's true, then we must now recall my viewpoint which is to only argue from Scripture on the merit of a doctrine.

Under these circumstances I am automatically in the wrong because if I ever find issue with how the Church Fathers interpreted then I should be immediately discounted because they are the defacto rule of law.

In essence you have elevated the Church Fathers above scripture,  because no matter what scripture says it will always be decerned by what they themselves said.  You cannot logically at this point say you are Prima Scriptura because the authority of the Church Fathers themselves exceeds scripture.  Why?  Because if I cannot argue from scripture against their point simply because of their supposed authority then they are not beholden to what scripture actually says but our beliefs on if they themselves were divine heralds of the proper interpretation.

To say that is true is to also say that they hold in their hands the infallible nature of God's Word.  They are essentially God's Word Part 2.  I do not believe we have touched on any actual doctrines in our meta overview of the handling of God's Word and it's position among the Church,  so I am not saying widely fabulous interpretations like Charismatics or Adamites are suddenly right under Sola Scriptura.  I'm saying their right or wrongness is ultimately beholden to a higher authority.  Be it bias, personal desire, or malicious twisting none of these have any part with the truth of the Bible when they are lined up alongside it.

Essentially your only real options are to continue shouting, "subjectivism!",  which while being an entire debate topic in itself I do not think correctly corresponds to the depth of the situation.  I do not say Calvin or Luther are an authority in themselves,  I say they are subject to the reality of Scriptural truth.  Insofar as the Law and Gospel, being the crux of the Bible, are concerned I believe them to argue faithfully according to the text.  I do not hold them to be infallible, and I do disagree with them on some points.  Does contention over the higher doctrines effect that the truth of what the higher doctrines are actually defined as exists?  It clearly doesn't.  Does contention mean, I as a Lutheran, perceive my Calvinist brothers to be unsaved heathen pigs?  No it does not,  for even through very different mindsets the same Gospel has been proclaimed by them and I.  However,  like I said this is a topic in and of itself, but it brings us to your argument.

The other option you have is to say that because contention exists, and is nasty, that clearly some higher tradition must exist to explain it all away.  The problem with that is manifold in that, contention has still existed in the Catholic church (Of which for some reason you aren't a part of even though you argue from Tradition), and that you are still left with the issue of "bootstrapping" Tradition into it's place of superior or equal status to God's Word.  The issue with that is that you are forced to prove it from Scripture, being the only verifiable Word of God given to us.  To say that Tradition automatically is granted this status is nonsensical.  The only place you can clearly articulate a tradition from the Bible is 2 Thes 2:15.  The issue with this is temporal and grammatical.  It's temporal in that "teachings we passed onto you" implies that at that moment all traditions were passed on.  It does not explain what traditions these are,  it doesn't even say if these have to do with Biblical interpretation,  and furthermore it also doesn't actually layout a system that specifies more men would come who would be able to make more traditions.  So we reach a temporal problem that all traditions must have existed perfectly at that moment, to say otherwise we would have to perform eisegesis on the text and throw it into a vague abyss.  However,  history will show that this has not been the case with the Catholic Church.  Matt 16:18 wasn't even codified until the 18th century (of which there was plenty of contention over the true meaning of it).  And I would love to see proof that Marian Doctrine existed in 55A.D~.  There's alot to get in over this,  but I would wager you that there is just as much contention over the history of Tradition being turned into Doctrine (Or whatever shape-shifting pedantry they want to call it) as their is over interpreting  the Bible.  Furthermore, we find no strong statements from the Bible on the extent or actuality of these Traditions (in full), nor statements over Church Fathers who would hold primacy over the interpretation.   Infact, we find the opposite in that the Holy Spirit would help us interpret, and instances like the Bereans where Scripture was the highest authority (logically leading us back into Sola Scriptura,  not Prima).

Secondly I say there is a grammatic issue,  that also ties into a previous one.  That is to say that when Paul says "whether by word of mouth or by letter", does that imply that they each held equivalent content?  If that is true, then Paul is saying that whether you receive the letters I've written by word of mouth or actual paper, believe them!  If Paul is not saying that,  then that would mean the letters and word of mouth are nonequivalent in their content.  If so it's surprising that we don't have a single letter from Paul outlining what he meant by all these traditions.  Neither do we have a single early believer who knew these traditions from word of mouth from Thessalonica who wrote them down letting everyone know the extremely important traditions Paul had told them.  The most we usually get is fantastical stories of St. Peter fighting Simon Magnus in the air with wizard powers.

In summary, Prima Scriptura is not a good deflection word; such that in practice the supposed authority of Church Fathers is elevated above scripture.  Tradition is not well documented,  has organic properties, is subject to contention, and must be proven from scripture for which the evidence is scant.  The issue of subjective wild interpretations is not in itself a problem which detracts from the objective self sufficient perfect truth of scripture.  The issue of Scripture not being self sufficient logically leads to a meta circular problem were neither Tradition nor Scripture can ever be verified.