Do you stop gaining weight after sometime if you don't step up your calories from time to time?

I have started consuming 3000+ calories a day, I track them on myfitness pal app. In a span of 15-20 days I have gained 2 kgs. The first week I averaged around 2700 calories which made me gain 850gm approx. I was very motivated since I have tried many times in the past with 2500 calories a day but found it hard to be consistent. Now after 15-20 days I see that I am probably not gaining as much as I did in my first week. First week - 850gm Second week - 600gm Third week ongoing but seeing the current trend per day, I think it will be somewhere around 500-600gm.

I want to ask if I keep eating 3k calories a day for the next few months, will there be a time when my metabolism catches up and 3k calories become my new maintenance calories? Will I start losing weight once I reduce my calories intake since I can't really sustain 3k for the rest of my life. I was thinking to go for 2k-2.5k once I reach 60kg atleast.

I do 30-45 min 5 days workout with resistance bands daily followed by 2 days stretching a week. I weigh myself empty stomach in the morning after having come from the lavatory.

Do you suggest me to just follow the diet and continue doing what I am doing? I would realky appreciate if someone who has been on same calorie target for a few months and continuously gained weight give some advice.

21 M, 46kg