Good morning everyone! This is very common for players who are just starting out in the poker world. The more you study, the more automatic your decisions become and you begin to realize that playing at several tables at the same time can be much more profitable.
It can happen that you play with a lot of concentration at a single table, on an MTT, and even after hours of intense play, your AA loses to a smaller pair, such as 66, 77, 88, etc. You spent two hours playing with full focus and suddenly you lose a hand and have to start all over again.
When you play at multiple tables, you just need to perform well on an MTT to make a profit. Many poker teams that study profitability establish a minimum number of MTTs that each player must play. When I was part of a poker team, the minimum was 600 MTTs, and that was precisely the period in which I made the most profit. The problem was that I had to pass on 60% of everything I earned to the team.
That is why, in my opinion, playing at several tables at the same time is much more profitable. You reduce the emotional impact of losing a specific hand or tournament and increase your chances of ending the period with a profit.