Any suggestions on where I should go to buy a new bike for 9 mile commute most likely taking a train to get closer so most likely it’s a 3-5 mile commute but Alot of hills budget is probably under 500

So I've commutted on my bike to work before in the past but the most was about 3 miles. Now I work a little further and make a little bit more money. But I plan on working out my body some more and getting to work on time because some of the buses is just not too reliable. I already have a bike that I've had since about 2020 and it hasn't held up too good. It's a huffy mountain bike with 26 inch wheels that I spent more money fixing up than the actual cost of the bike. Ive been thinking I want to get a new bike that I can ride up hills with and travel far but figured I should also be looking for a bike with bigger wheels than 26 inches. Only problem is that my huffy that I've had since 2020 I ended up buying from target. And when I bought it from target I noticed that targets bikes aren't all that good. N me being somebody that used to work with target I did notice that their bikes aren't the best. Definitely something a little iffy with the assembly. I think I still want to buy a mountain bike but I noticed my bike is just a little too heavy. I'm not sure how normal it is to have a bike that is so heavy but I don't think it's good if your doing a lot of traveling on it.

Is there any suggestion anyone can give me on my quest to find a new bike or whhere to find it. What kinda bike to get for riding up hills and weight comparison. Just need the smoothest experience to get to where I need to go. Also not trying to break the bank. I definitely plan on getting a car soon. I still feel like I would love to ride my bike to work even if I get the car because I need the workout and riding is the closest thing to zen that I can think of currently.

Also I have to mention my local bike shop I've been going to for years has just alienated me Alot due to some shady deals I've done with the company that seemed like he overcharged me a bunch of times. Last time I went to get my chain replaced and he charged me 34 dollars and got mad at me when I remember talking on the phone a week before and getting a whole other price. Dk if I want to give him more money especially after last time even after knowing I give him a tip Everytime he does work on my bike…. I don't know if any of this makes sense but I just need to know where to buy a really good bike to travel far. That not taxing on the body but is durable to get me from a to b. Please help