Need Assistance Figuring Out Specific Repair (2013 Kia Rio Hatchback)

Hey all! so i am the owner of a 2013 Kia Rio Hatchback with about 160k miles that is my first (and so far only) car. (for context, i live and rent on my own, finances are usually pretty tight so i bought this car for cash because i dont think i could afford a car payment).

i bought it about 3 years ago, and i do my best to keep up with maintenance (got all 4 tires replaced, new spark plugs/fuel filter, new battery, consistent oil changes, etc) but it still has 2 major issues.

issue 1: sometimes, when the car is idling or stopped for a while, the battery light/oil can light pops up and the engine randomly shuts off. it also has happened while the car is in motion too.

issue 2: the RPM meter sometimes drops to 0 while the engine is running. it just gets stuck in one gear but is usually still drivable.

i asked my dealership mechanics what caused issue 1 and they said it was a loose battery casing and that they couldn't fix it. the engine stalling is a huge problem during the summertime, but practically nonexistent during the winter.

is there at least 1 or 2 pertinent repairs i could make to keep this car, or do yall think its time to bite the bullet and just start saving to get a new one?

i know absolutely nothing about cars or how to fix them. i have had no idea where to get help for the past few years, and today the engine stalled right as i was crossing a big intersection and i genuinely got scared of causing an accident.

any advice would be greatly appreciated !!! thanks in advance :)