When to exchange the queens and when not

The mistake that costs title Champion of Thailand

Today finished Thailand Championship.
A very tough fight was going between one of our ChessMood PRO Members Thanadon Kulpruethanon and Tupfah Khunokaew, a very talented and underrated guy.

In the last round he was playing against my another student Prin, and in case of a win, Tupfah would win the tournament.

In this position, he played Qe5? A move that costs him the title.
Why white shouldn't change the queens?

1. The black king is not safe due to weak dark squares.
2. Queen + Knight is doing much better than Queen + Bishop.
3. Rook + Bishop work better than Rook + Knight
4. Bishop gonna be better than the Knight as the fight gonna be on two sides of the board.

To understand when to exchange pieces is a must-learn skill!

Anyway, great tournament by Tupfah and congratulations to the champion Thanadon Kulpruethanon!