Without a photo showing what is happening, all we can do is guess :-) First, it is important to know where you are located......mangos are a tropical fruit and require a frost-free environment so a deck siting may or may not be appropriate. And we need to know what sort of potting soil it is in - watering 3X a week may be excessive or maybe not, depending on the soil consistency and ingredients. And when you might have repotted it, if ever.

We just need a lot more info before we can make any assessment.

Sorry, I'm not sure why exactly the photo would not upload earlier but here it is. Currently, I reside in the state of Pennsylvania by Philadelphia in the Hardiness zone of 7A. The soil is any regular potting mix you would by from any home improvement retail store, like Home Depot-https://www.homedepot.com/p/Miracle-Gro-25-Qt-Potting-Mix-72781430/206457033, this would be the exact one. I have re-potted it a few months prior due to a lack of growing space.

1) It is far too cold to have this plant outdoors in your area at this time of year!! Probably should have been transitioned indoors in September. I would guess much of what you are seeing is just cold damage.

2) The vast majority of container gardeners, whether it be indoor houseplants or outdoor containers, find prebagged potting soils - and especially Miracle Gro soils - highy inferior. They tend to be heavily peat based so too small a particle size, too easy and fast to collapse or compress and too highly moisture retentive. Amending that with 50% perlite or even better, making up a custom bark-based mix like the 5-1-1 mix would be far more desirable.

Alright thanks for the information.