Absolute nonsense. I have been a Christian for 65 years and I have never found any problem in agreeing the doctrine with all whom I knew in all churches..
Then you have never looked hard enough.
The protestant mantra "agree on the essentials" is a non starter, because all the differences were plenty enough to force them to fracture and fracture and fracture again. Differences so profound that they are no willing to stay in the same congregation as those they disagree.
Some do not have this problem like Anglican and presbyerian, but onlybecause what they believe is so varied, nobody can any longer work out what if anything they stand for.
But I listed the differences so many times. Here just a few.
All mutually exclusive,
Five different versions of eucharist, from real flesh and blood, to just a memorial. The difference between those is profanity itself.
At least three different versions of baptism.
At least four different versions of salvation from OSAS to not saved till the end.
Other sacraments vs no sacraments and many different flavours.
Charismatic variants. Lots.
Modalism vs trinitarianism. Try to get a pentecostal to explain how one mode can talk to another? Beats me!
Bishops and clergy, essential for sacraments , desirable, possible, or impermissible.
Single , double predestianation or none.
The destination of the child who dies before baptism, One church certainly fractured on that! They cannot stick each other now!
And many , many others.
Then the new stuff which panders to populism not christianity
Pro life vs pro choice. Both abortions and contraception attitudes.
Gays vs women vs men as pastors.
Divorce and remarriage
Now take the permutations of belief.
5*3*4*5 *3 etc etc etc etc
You RAPIDLY get to well over 10000 permutations.
And only one can be what the holy spirit states, yet all believe they have his imprimateur,
So all of them but one is wrong and preaching false doctrine, like almost all on here ,but who?
My life long quest was to find the right one since almost all protestants are provably wrong.
You betray your lack of study of any of this valiant.