I think that your Diamondback should be fine. Also, there is a shortage of bicycles and parts right now due to the pandemic so giving your existing bike a tune up might be your best option anyway. If you're interested in a new bike, that is certainly fine but just be advised that your selection is going to be limited and depending on where you live you may not even be able to find a bike your size. I just purchased a new bike and I had to drive 7 hours to the store that had one in stock.