Monk fruit and stevia both have a nasty back bite that kind of defeats the purpose of a sweetener in my opinion. It’s like when your mom used to crush a pill and try to hide it in a spoonful of jelly. That being said they’re not useless
Sugar alcohols like erythritol, sucralose, and my absolute favorite allulose all taste like sugar but lack the depth of flavor cane sugar has. And many folks have digestive issues when your personal threshold is hit, GI distress and or diarrhea. I haven’t had any issues with sugar alcohols but I mostly use sweeteners in the context of savory cooking to balance salt and expand flavors like with Asian food.
The best combination sometimes is a sugar alcohol with an herbal sweetener enhancement like stevia or monk fruit especially when the sweetness is the main goal like in baking a cheesecake. You have to be careful buying pre mixed sugar substitute formulas. Sometimes they add not so great stuff to them like maltose. Always read labels carefully and google ingredients your not familiar with. There’s several articles on the net about keto sugar substitutes, read a couple and learn about them.
As @Janie said you need to taste as you go sometimes with keto substitutions. I always try to buy the pure sweeteners so I can mix them to find the best combination for the purpose but I love allulose because it’s the most sugar like in behavior. You can make fully saturated syrups, brown and caramelize, make candy etc. It’s about $9 per pound though so I use erythritol when I can instead. But allulose works for anything and is about 70% the sweetness of cane sugar. This is where you can enhance with stevia or monk fruit to make up some of the difference or add more sugar alcohol. I recommend stevia drops for this purpose. 
Hoosier Hill Farm ALLULOSE Low Calorie, Zero Net Carb Keto Sugar, Natural Sugar Alternative, Made in the USA, Granular Powder, 2 lb bag, batch tested gluten free https://www.amazon.com/dp/B07HJGHLXT/ref=cm_sw_r_cp_api_i_TVETCbBHE9FV6
Erythritol Sweetener Natural Sugar Substitute 3lb - Granulated Low Calorie Sweetener High Digestive Tolerance Suitable for Diabetes Keto and Paleo - Baking Substitute Non GMO https://www.amazon.com/dp/B079X4G97G/ref=cm_sw_r_cp_api_i_3XETCb64PW4TD
Good luck with your keto baking. 