Is it possible that instead of a player, the computer can play against me without my knowledge?

I don't consider myself a strong player and I'm not looking for any personal entitlement. My opponent is stronger than me based on the data. But the course of our game and later watching some of his other games made me think.
For clarification. White pieces on my opponent. Game time 5 minutes. The opponent starts 10 seconds before his time runs out and wins by using his skills and speed of moves.
And the question: Is it possible that I played with a computer?
Another thing, not at all related to the previous story.
Is it reprehensible to provide anonymous, knowingly false information about yourself (I play with a 100-year-old opponent, which is rare to my knowledge (?) and surprisingly, I indirectly find out later that he is actually younger)? A LOSS to him is not a motive for me, but purely unethical (conscious) deception by a really strong player. I have considered chess players to be ethical people all my life. For a similar reason, the sport in general has lost a lot in my eyes.
Greetings Ants Pihlak

The computer cannot play directly here. Those who use the computer's help have to enter the moves themselves and cannot do it as quickly.
So you were either played against by a strong chess player or you made childish mistakes yourself (like I sometimes do).

Thank you again. But in the games of the opponent I observed with other chess players, the same player did not show the same pattern that had caused my doubts. The question is also interesting for me, how much the effect of different tools used could affect speed (for example, using a touch screen or a mouse). Physiological processes can undoubtedly also have an effect, including the use of recreational drugs (it is common knowledge that doping substances are drugs). I have only used a psychostimulant once in my life, as a student. Then a page of the syllabus appeared in front of me before the professor finished his question and "I sang quickly like a bird" in response to him, in his own words, "a beautiful song". He took questions during the exam without using tickets, he was even considered a bit mean, later such an action was banned.
I think I'm a bit of a professional cretin as an old (76 years old) retired doctor. I thought my opponent was strong and was mentally prepared to lose, so to speak. If he hadn't arrogantly let the clock tick before the game started, this discussion probably wouldn't have arisen.
Sorry to bother you, you have your own urgent problems anyway. I have no personal emotional experiences about my losses, but even at this age I am interested in the reality of how things happen.
Be healthy!

I once played chess at a table with a time control of 3 min 2 sec per move and discovered that I only had 2 seconds left to think. To gain time, I had to make short passes with the flag, and then I managed to win the game.
My opponent later admitted that he was nervously watching the clock, waiting for me to run out of time to think.
So his mind was on the wrong thing.
Here, some chess players also start playing with me later and then I tend to get carried away by the opponent's fast pace and become careless. Maybe this is a cunning tactic of the opponent?
During the Soviet era, they wouldn't let a chess player into a blitz tournament because he was heavily intoxicated and could barely stand. I helped him sit down at the table and only allowed him to get up when he needed to go to the toilet. He won the tournament and became the district champion, because his opponents underestimated him.