I’m not a lawyer, but anyone saying “it’s time for the 25th amendment” doesn’t know shit about the 25th amendment. Here’s the text of section 4, which is the part that allows the president to be removed from office:

Section 4.

Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.

Thereafter, when the President transmits to the President pro tempore of the Senate and the Speaker of the House of Representatives his written declaration that no inability exists, he shall resume the powers and duties of his office unless the Vice President and a majority of either the principal officers of the executive department or of such other body as Congress may by law provide, transmit within four days to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office. Thereupon Congress shall decide the issue, assembling within forty-eight hours for that purpose if not in session. If the Congress, within twenty-one days after receipt of the latter written declaration, or, if Congress is not in session, within twenty-one days after Congress is required to assemble, determines by two-thirds vote of both Houses that the President is unable to discharge the powers and duties of his office, the Vice President shall continue to discharge the same as Acting President; otherwise, the President shall resume the powers and duties of his office.

If you’re illiterate or allergic to Constitution-speak, that means that the VP and a bunch of Cabinet members can get together and say “he can’t do the job, he’s not the president anymore”, but the president can just say “yes I can and yes I am” and it doesn’t count. If they really want to fight over it, it goes to Congress to decide, and if Congress wanted to get rid of Trump they would have already.

It’s not a viable option, and anyone telling you it is is badly misinformed at best.