Aaq, you’re conflating new ideologies with new solutions.
I have no issue with new solutions. Gedolim instituted them throughout history, including bais yaakov, kollel, requiring kabalah for shechitah, cherem rabbeinu gershon, and many others.
The issue is in ideology. Bais yaakov did not come and say “the mesorah is that girls learning Torah isn’t so important, but WE say it is” rather, they said “we need to address the problem of girls not having strong yiddishkeit, because the home isn’t enough anymore”
Rabbeinu gershom didn’t say “the Torah says it’s fine to have multiple wives but WE say it isn’t” rather, he said times are different and it is no longer feasible, people are irresponsible etc..
But rabbi kook, rabbi yoshe ber and the Lubavitcher rebbe changed ideologies, and the former 2 added in blatantly non jewish ideologies into their judaism, making what reb elchonom succinctly called “judaism mixed with avodah zara”
This isn’t a regular machlokes, it’s one side calling the other invalid, because they admittedly, openly grafted on non Jewish philosophy into Torah.
The Lubavitcher rebbe, did not openly inject outside ideologies, but his novel ideas are outside the mesorah – we don’t find them in any chasidishe group, including chabad, before he took over.