There is nothing wrong with what you pejoratively call "a mishmash of doctrine", or what we would call today "the free market of ideas". The only problem is the epistemic pride of those who are so certain they are right that they believe they are justified to disparage and bully and emotionally manipulate and even persecute others into submitting to their superior knowledge.
We should be epistemically humble enough to present the case we have for our beliefs, and to allow others to weigh that case and make their own decisions without how persuasive it is. Cancel culture is not epistemic humility.
Unfortunately, too many seem to still fit into the mold of what Paul was dealing with:
NKJ 1 Corinthians 3:1-4 And I, brethren, could not speak to you as to spiritual people but as to carnal, as to babes in Christ. 2 I fed you with milk and not with solid food; for until now you were not able to receive it, and even now you are still not able; 3 for you are still carnal. For where there are envy, strife, and divisions among you, are you not carnal and behaving like mere men? 4 For when one says, "I am of Paul," and another, "I am of Apollos," are you not carnal?
Well, my pastor says...
And then with the various systematic traditions, we have another level of the problem.
I've watched a few "exegete" Scripture by analyzing every word as far as it can be parsed and interpreted, analyze every grammatical structure, and fit it all together where I was essentially in agreement with every point, only to then have them take a leap to fit it into a systematic theology when there was no way that one verse or section of Scripture could be taken there apart from a tremendous amount of yet unfinished work, which could undo the premature conclusion.
We're still arguing for many reasons, a few of which I've just identified.
Make sure the Only Foundation (1Cor3:10-11) is accurately laid, grow a bit, then just let the Word speak and learn to study and interact with IT/HIM by His Spirit and with others who are doing the same.
"epistemic humility" is mostly unknown in the church today and we seem a very long way from corporate maturity:
NKJ Eph. 4:13-15 till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ; 14 that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, 15 but, speaking the truth in love, may grow up in all things into Him who is the head-- Christ--