Do I have to stick to factory recommended coolant if this 22-year-old car

What is your question?

I'll be 2000 Buick Century custom 3.1 L just over 200,000 MI I've never put the decks cool coolant in it which is recommended on a sticker under the hood should I always use that cuz I've been running 50/50 and the car seems underpowered won't kick into the overdrive gear or passing gear if you push down on the accelerator it's not smoking or else clean everything's all right everything's been been renewed under there you know a service but that light is on service engine light is on and coolant it's never overheated but should I stick to the factory recommended coolant even after 22 years not knowing if previous owners used 50/50 cuz it seems to me that the car is underpowered in it the water boils quite often in the coolant reservoir but never the radiator just never overheated and it doesn't leak

What makes this problem better or worse?

Long period of driving on freeway or interstate 65 70 mph during the daytime it's worse when it's hot outside I have to play with the air conditioner and cooling and heating switches on the control panel for the air conditioning to get the engine to cool down the gauge will go back down to the right level but it's never

How long has your 2000 Buick Century had this problem?

Several months and I don't know the history of the previous owners before my this car was gifted to me from a friend of mine that was going to give us gifted to him it runs perfectly fine just is underpowered and I'm just wondering if I should just stick to the recommended coolant that's on the Stick Run of the hood but it does get hot but it's never overheated and it slows it down bogs it down and it loses engine power you know as far as the can I get suggest it seems like it's underpowered at that time