Stuffing

I ate 6,000 calories every single day for a month during the lockdown last year, and I gained 23 pounds of pure fat. So if you're actually able to keep it up for three months, you'll gain a ton. But it's very difficult to maintain that level of caloric intake, especially on top of other responsibilities (work, etc.).

What kind of stuff are you eating? The most challenging thing about gaining for me is just finding enough things to eat so that I don't get tired of them. It feels like the choices are either spend a fortune on fast food or eat the same things over and over.

Well for an estimation,
We have 80 days left in this year.
If you eat 7000 u will consume
560 000 calories.
Estimating you need about 3000 for maintaining—> you need 240000.
So there are 320000 open calories witch if you not only eat 7000 calories but also utelize them equal 45 Kg.
But this is just the math, in real life 50% should be possible.

Since there are a couple of mechanisms that do prevent there rapid Weight gain.

I always try to consume as many calories as possible, for 6 months I tried 10k a day, cheap snack food and Chinese helped, mixed with cakes and heavy double cream.
Burgers are good for gaining calories