No no no!
Shake replacements aren’t worth it.
To lose weight effectively and consistently you need to retrain yourself to eat the right amount and this takes time. A shake diet won’t do that as you won’t learn much except they taste pretty crap and you really really like real food with textures. 
Slimming world is OK but I don’t like the points system of it and similar because it feels disconnected from real life to me (disclaimer, yes it works for some people. Fab, it’s just not for me)
You need to know portion sizes and food weights per portion and how much to eat to really change your eating habits. And you can only do this by actually weighing it and cooking it and eating it and figuring out what makes you feel great, gives you energy, makes you poop regular or what saps your energy and makes you feel bleugh.
Eg I don’t eat super fatty meals, too much yoghurt even though I love it or a carb heavy meal because if I do the fatty food makes me feel bleugh. Yoghurt can lead to hangover feeling and carbs make me want to nap. I love lightly cooked tomatoes with garlic on top of my salad and makes the whole thing taste infinitely better and I want to eat it all the time 😋
I relearned all this on the first few months and things I loved I don’t fancy so much now and things I hated I want to eat all the time.
I’m about 4 months in to weight loss. Focusing on eating a calorie deficit based on my weight and height ( no points or syns or shakes in sight) it’s working and I’m losing on average 1.5 lbs per week and even lost weight over Xmas whilst still enjoying mince pies and quality street. I can easily judge a meal with the right calorie content/portion size for when I’m cooking now so I don’t always have to weigh it out etc just tap it into my tracker app. I still weigh it out if I’m doing a new recipe or trying a new food out.
I’ve not put in consistent exercise yet (covid, sen kid, it’s bloody hard to do anything right now) and I’m well aware the next 20odd lbs of weight loss will slow down until I can get my fitness up.
Give yourself time to figure it out. Expect fuck ups and a bad day here and there and get back on it the next day.