It's not worth holding on to your 2016 Renault Duster diesel MT as it is almost 10 years old and at 1,30,000km, has already lived its best life. As the model is long discontinued, parts availability will prove to be an issue in time; given its age, bigger issues will start to crop up (such as the suspension, as you have pointed out), and yes, it's not as safe as modern cars with higher mandated safety standards.
Apart from all this, with ever-tightening emissions regulations, an old diesel engine like the 1.5 K9K will become increasingly difficult in the future.
It's a great time for an upgrade, as there are many new models arriving soon. For one, the new-gen Renault Duster will arrive on January 26, and promises to have everything we loved about the old car with more creature comforts. It will no longer have a diesel engine, however, but given that your usage is going to be lower, it could work out just fine for you. If you must still have a diesel, check out the new Kia Seltos, which will be launched on January 2, 2026. While not the most powerful engine, it is smooth and refined, and the Seltos, on the whole, is an excellent package. 
