Kia has more tech compared to hyundai of the same year. I sat and drove both cerato and elantra (friend's vehicle). Can't go wrong with both.
Just look out for wear and tear items (suspension and brakes) and standby few k's to repair if needed.
If buying 2nd hand, check engine cooling system (hoses, radiator fan etc) and also the aircon when car idle. If aircon hot when idle and cold when driving, need to repair the valve.
One issue with Kia is the catalytic converter also. Fails earlier than japanese cars (suggest change to aftermarket high flow cat con ~rm500).
Another issue for both models is the steering wheel clock spring ~rm250 to fix.

I'm using Kia Optima, know quite a few people using Korean cars. Good value for money.

No issue with gearbox and compressor, so far the biggest cost of repair is changing the engine piston ring which cost around RM2,000. The other spare parts & sensors all around RM300-600

I think it's wear and tear, the workshop I trusted say if not replaced it might start leaking oil. Given the car already break 100k mileage that time I think such major replacement would be expected. The other parts which I remembered replacing are steering clock sensor, airbag sensor, alternator, break pump, power window motor(driver side), and  radiator (this one is my own mistake causing overheat), most of them between RM300-600 each.

If you are getting the car above 100k mileage I think you should expect changing 1-2 parts per year beside regular maintenance

If you can accept the maintenance cost (1-2 parts every year beside from regular maintenance) then I think you are good to go, for me the car is quite reliable, a bit underpowered but enough for city drive, and the exterior look still modern enough.

RV is non issue since you won't be getting new car anyway (the latest 1.6 CBU model cost 134k++ which totally not worth). I think old people still have bad perception towards Korean car but for me it's not much different with Japanese car except maybe the availability for some spare parts. I would say low RV is actually a plus point for second hand car buyer since you get the car with lower price as compared to Japanese brand from same segment and years, the money you saved is a lot than enough to maintain it for next few years to come.

How long you plan to loan?
I have been driving cars with low RV(hybrids, korean car, french cars and coupe) but have no issue to sell it because my loan tenure is max 4 years. and I have been changing cars every 2 years, so by the time i planned to change the car, the resale value is enough to cover for the outstanding and some left overs for new car dp.

You can try compare the RV of these car on car listing website to gauge around how much depreciation per year. The depreciation will be getting lower and lower over the years so it might not have much different if you are getting a >7years car. I think the decision is based on whether you willing to go for B segment car, like what you posted if you want a C Segment then the Japanese brand will cost at least 10k more which also mean more insurance cost.

Seriously if RV is your main concern and your parent's opinion is important (e.g. they are sponsoring the downpayment) then just go for Japanese brand. No amount of information can change their mindset unless they personally own and maintain one.

In used car market, 1st owner will always take the hardest hit on resale value. Subsequent owners will normally just follow whatever leftover of the market value of the car. Why overthink on the resale value when you are aiming for a pre-loved unit? Isn't it clear as daylight that you are going in to pre-loved market that 1st or other owners have taken the hit? Instead of worrying about RV, your focus should revolve more on the actual condition of the pre-loved cars of your choice. And for this 1 reason, I have advised you to go for direct purchase from owner, NOT 2nd hand car dealers. Seems like you missed that piece of very important part. FYI 3/4  of my cars are pre-loved, and NONE went thru 2nd hand car dealers.

All the best to you.

No electronic sensor failure on my Optima. Only the Check Engine Light came on for faulty O2 sensor/front catalytic converter (P0420 code). Replaced the front cat con to SS extractor for performance instead.

Repairs I've done over a year of owning the car:
1. Change projector housing and HID to led. Projector housing coating started to corrode/oxidise until 1 side doesn't reflect the light properly. Cost RM 1k total.
2. Change new compressor, condensor, cooling coil and actuator valve. Aircon hot when idle, cold when rev, should be same issue with Cerato. Cost RM 2.8k total.
3. Change suspension parts due to wear and tear. Stabilizer link, bushing, link arm, steering yoke, absorber mounting. Cost RM 800 total.
4. Change spark plugs bcos 1 cylinder misfiring. Cost RM200 total.

I would say electronics failure is very rare for the cerato and optima, its either mechanical or wear and tear parts. I would standby RM 5k for repairs once you get the car just in case.

My friend's elantra bought 2nd hand in 2019 (2015 model 1.8) -> change suspension parts due to wear and tear, steering wheel clock spring.
My friend's cerato bought 2nd hand in 2020 (2015 model 2.0) -> change absorbers and control arms due to wear and tear.

There are reliable workshops around that specializes in Korean cars and frequented by FB Kia group members.
Penang has 1, Johor has 1, KL have a few.