Dutch Miller Kia review: Kia optima, car has no acceleration

My 2019 Optima all of the sudden, while being driven, just bogged down and would not accelerate very quickly. It would not allow my husband to go any faster than 19 miles per hour, the RPMs wouldn't even go up to 2. This occurred on Monday August 12, 2024. The car was towed to Dutch Miller that evening. The car has been at Dutch Miller Kia, in South Charleston, WV since Tuesday August 13th and has not been looked at, because they "don't have enough mechanics". This should be able to be diagnosed quickly and easily, even in the parking lot, correct. I need to know if it is the engine, since quite a few people I know, have had to have theirs replaced. If so, then will Kia give me a rental while it is being worked on? The car has 60 months coming up in the middle of September and the milage as of the time of incident is 59,738. We have an appointment on September 4th, but I would like to know what is going on with my vehicle and get a rental car if at all possible and quickly as possible.