My turn to ask for plateau tips

I'm F32/172cm and lost about 20kg (110kg to 90kg) from March to today. However I'm stuck at about 90kg for the past two months. Average weight for the last 3 months according to my app is 91,4kg for December, 90,9kg for January and 90,2kg for February. So at least I'm still losing a bit. I achieved a lot of the loss (about 15kg) through an (accidental) overdose of thyroid medication and liver problems. So not things I want or should repeat. The last 5kgs were mainly calorie counting and exercise, specifically running. I have knee problems, so the goal is to reduce the weight a bit faster until I'm at least at 74kg/healthy BMI. Goal would be about 0,5kg/week. Here is the thing: I know what to do. I have my meal plans, they are high protein and high fiber for European standards (so about 70-90g protein/day which is more than my lean body mass and about 30g fiber/day). I don't drink a lot of sugary drinks, mostly water and unsweetened tea. At the moment I plan for about 1200kcal (not because that is my goal, but because I know there will be snacks, see later paragraph). But according to my app my average calorie intake is about 1700-1900kcal. Realistically it is a bit higher because I don't track snacks that accurately and I occasionaly (1-2x a month) leave out very high calorie days. I don't want to change leaving out some days, because they are needed for my sanity and I hate tracking on special occasions. My absolute enemy is snacking. I'm often (literally 3-4 times a week) at friends, playing board games and pen&paper, and there are always snacks. I always tell myself I won't snack or just will take a little bit and I always fail. I try eating big meals with lots of protein beforehand, it doesn't change anything. I tried telling people to leave snacks at home, but that doesn't always work and I don't want to ruin snacking for everyone else. Why should I spoil their fun? The other enemy is shopping during the week. I normally do one big grocery run on weekends buying healthy, good stuff, but somehow I end up in the supermarket anyway 2-3 times a week and buy/eat high-calorie garbage. Yeah, so looking for tips to change/ameliorate those two behaviors of mine. Especially tips on how to avoid snacking, when snacks are present, I'm just not a very disciplined person and I don't want to reduce my social life or forbid my friends to bring snacks.