Welcome
@corwnlyn
Good decision to get yourself a meter, without one it's impossible to know if the changes you make to your diet are effective.
Random Tests throughout the day will just give an idea of your levels but other than that no real useful information.
Test just before you eat, this is your base level. Eat your meal then test again around 2hrs later.
The difference in the two results will tell you how that meal has affected your sugar levels.
A non diabetic person would generally see their sugar levels return to around the base level within the 2hrs.
We generally allow ourselves a buffer of 2mmol, so if your post meal level is no more than 2mmol above your base level, you can consider that meal a keeper.
If however your 2nd test is more than the 2mmol above base line, then that meal had too many carbs for you to process efficiently. Armed with that knowledge you can rethink that meal, find a way to reduce the carbohydrate content, or if your level was way over the 2mmol maybe consider dropping that meal altogether.
Your 150g of carbs would be more than I had in 3 or 4 days, it's possible it could work for you, who knows, let your meter decide.
I didn't particularly want to do a keto diet either, but it just sort of happened. When we burn fat for energy, the fats are broken down into ketones and they are used to fuel your body. Anybody who has ever lost any weight has burned ketones to do it. And if you think about it if we are having trouble using glucose, it makes sense to burn the energy we can use