A lot of what I’ve seen in the past comes down to more internal process improvement than a new tool. Usually a new tool doesn’t fix the inherent problems but just makes them more difficult to root out. Usually for good supply planning a good system is a result of clean data and disciplined processes. For example, do all your items have vendors, pricing, lead times, reorder points, purchase history, etc?
Do you have good forecasts from your sales teams based off historical sales and can they accurately provide upcoming forecasts monthly or weekly?
Are all your item masters setup with all data correct to quickly flow through the purchasing system?
While many tools promote the usage of AI to help predict and enhance your supply chain the fact remains that bad data will make any system difficult to use. To that end I find that focusing on managing your item masters, processing your purchases through NetSuite correctly and effective forecasting can have a huge improvement and all this can be done using excel and Google sheets
All that being said I’ve heard good things about NetStock and DemandCaster
The native Demand Planning module from NS is not great. The MRP is much better and works fairly well but I would not use it if you have tens of thousands of SKUs or multi-level assemblies to plan
Hope this helps