Interesting.
I have a friend who has used a Hotshot for a while for urban commuting ... very leisurely, a lot of riding to the bus stop, racking the bike, and riding away from the next stop.
The bike is made for that stuff. Anything much more than that, I wouldn't trust it. (
https://www.walmart.com/ip/700C-Mong...ange/143302742)
The bike has a 7-speed freewheel hub, which isn't as strong as the modern freehub design, no front derailleur, and a lot of cheap plastic and stamped-metal parts. It is a fine bike for getting bsck into riding, and with good maintenance could last a long time, but I wouldn't trust it for hard use.
Have a shop look it over, certainly. The assemblers at Walmart are notorious for making simple yet dangerous errors, as well as ignoring things like basic lubrication. Then, just go out and ride it as much as you like. Check it before every ride (no matter what bike, but Much more important with a cheap bike): shake the bike, bounce it a little, listen for rattles, tap the spokes to check spoke tension, spin the wheels to make sure they are straight, shake the brakes to make sure they aren't loosening up .... shake the handlebars and spin them to see if the headset is tight but not too tight. Push the bike and squeeze the brakes to make sure they are adjusted properly--(not something you want to find out when you Need to stop.) Shake the wheels to see if they are solid side-to-side--bearing adjustment and axle tension.
Then just ride around for several months until you decide on a next step.
If the bike meets your needs, there you are. If not, we can send you in lots of other directions.
The saddle might be cheap, but it isn't necessarily bad. Probably since you are new to riding you are putting most of your weight on the saddle and that is Not what it was designed for. Your legs should carry most of your weight, and you hands a small amount, with your seat bearing a slightly greater proportion---but the vast majority should be supported by your legs.
Also, check the seat angle and the overall fit. A lot of people have the seat too low, and sit on it like a chair, and have the angle a little off, so that it presses in unpleasant places. Everyone is different and you will need to experiment.
I assume (?) that you have a spare tube, patch kit, portable pump, tire levers, and a multi-tool which has at least three allen wrenches, all in a small bag under the saddle. One of the allen wrenches will fit the seat collar (up and down) while another should fit the seat clamp or clamps (saddle tilt and fore-and-aft.) The bike shop will be able to help you with all that stuff. (Oh, and consider a Serious tail light if you ride in traffic---day or night. Headlight too if you ride at night.)
DO NOT "upgrade" this bike. It simply is not worth it. Do not put anything on this bike you do not intend to take off and install on your next bike .... which you Will (almost certainly) need if you find you like cycling. Give the saddle some time, and if it just never works, then you, like many of the rest of us, can embark on the long and sometimes frustrating search for the "right" saddle for you. Once you find it, you will want to keep it. Other than that. I would not replace anything on the bike. No part of it is of sufficiently quality to justify hanging any quality parts on it.
There is nothing Wrong with your bike. If you treat it gently and keep it maintained you should be able to ride it for years ... or perhaps not. But if you really like cycling you might find yourself wanting something much lighter, sturdier, and more functional. It depends on what you want the bike to do. It might meet your needs ... but there is a reason many of us pay ten times that amount for an "entry-level" bike ... because we are entering the world of "cycling" as as opposed to just riding a bike around.
Pardon my pretentiousness, but there is a reason there are econoboxes with vinyl floor mats and AM radios, and Porsche 911s, Corvettes, F-150s, Serious 4WD SUVs, fake AWD "SUV" minivans with hoods for soccer moms, and such .... each vehicle does specific things well, and All of them are vastly better than the $13K "loss-leader" no-frills, no-options econobox---unless you just need the cheapest thing which will get you to work each day, in which case ... drive a Yugo or whatever is the modern equivalent. A ride is a ride.
But ... if you find you Like cycling, you will appreciate what the better machinery offers. Your bike and a Giant Contend, for instance, will both get you around town ... but one will probably offer a lot more utility and be a lot more fun in a lot more situations. But for now ... just add up the miles, or the hours, or the smiles, or however it works for you and keep the pedals turning.
None of us here can agree about anything except maybe that riding a bike can be a really great way to spend life. If you find it so ... well, great.