Yep, had DS in 2018 - I think a good quality one too, and gained about the same amount over 2020-early 2021.
I know exactly why too. Too many simple carbs (breads/sugars, chocolate and candy), processed convenience junk foods, liquid calories (sugary coffees, lots). Also lack of exercise/activity due to staying home, as well as being placed on a prescription known to cause weight gain contributed to the regain.
I simply got over-confident after a few years living with the surgery.
Simple refined carbs are our surgery's achilles heel. We do not 'malabsorb' simple carbs, we absorb them 100%. Simple carbs, for me anyway, tend to be slider foods - breads, pizza, sweets/candies/donuts/pastries, and of course liquids like 800 calorie Starbucks don't spend long in the sleeve. Those two issues spell trouble for us, at least they have for me.
Good news is once I eliminated the junk foods, simple carbs - and switched to a high-protein, low - carb diet, the weight has been melting off. I was concerned that losing regain would be difficult after the initial massive weight-loss after the surgery, but that has not been the case.
I can accurately report that I've lost about 14 pounds in the last ~28 days. I have been calorie restricting in addition to the low-carb/high-protein diet, but the sleeve component of the surgery has made that rather painless, and I'm not starving at all.
Just get back to basics and I think you'll do fine.