On the right side of the car front or back. I changed the fuse but no help

So I got an oil change yesterday and the battery was checked. It showed to have a good life..
Today my car wouldn't start without a jump, I drove the car for 30 min, no battery symbol was on. But as soon as I got home, I tried turning it back on and the car is dead again. Is this a battery issue?? Or an alternator issue, I know that there is a recall on the alternator and valve gasket , but I need to know if it could be something else

dealer said it was battery. Purchased brand new battery and it was a waste of money. Old battery was good. Car would not start the next day. Two other mechanics worked on it to no avail. Once car was jump started it would run for a day. Car is still dead in drive way. This has been going on for six months. Car only has 48,000 miles. Not reliable. Why can't this problem be fixed already? Shouldn't Hyundai mechanics know how to find a fix a problem?

After the car has set all day or when I first take off I feel the vibrating under the gas petal

The emission system has been replaced at a cost of almost $1,000.00.

We just bought this santa fe with 130K kms. We have noticed a gasoline smell when driving, and it leaves drips sometimes after parked. The drip seems to be coming from the front drivers side, and it's gasoline.

It is a 3.3L V6.

Today, I heard that my santa fe had many problems. Hyundai dealer shop ask me to replace radiator, fuel senders, and both front struts. It costs $2,000 so I would like to fix them as possible as I can. Which one can I fix it by myself?
Please give me some advise

Check engine was for few months now. But dealer is saying Hydraulic pump and fuel sending unit plus break switch change @3500 plus tax

This sounds too much and when I check I can't find anything like Hydraulic Pump

Fuel gauge goes always drops to Empty after I go below a 1/2 tank... Also the check engine light comes on as well. When I fill it, the light goes off and the gauge works properly. Once I hit the half tank mark, it drops and the light comes on. What can cause this?

97,000 miles. Told they were separating and total cost is $375.00

How much does a new alternator cost