Maytag Gas Dryer not drying

Our maytag gas dryer takes awhile to dry clothes. A medium load in the dryer takes about 2 full 70 minute cycles and some more time. The dryer doesn’t seem to get very hot inside if you just open it in the middle of a cycle. It gets warm but not hot. I’m assuming this is why its taking awhile? Any help would be appreciated or things to look at first. I have the drum belt to replace as well and will purchase other parts if necessary but we have no plans of sinking alot of money into a 20 year old dryer. Thanks