It should be just fine in the system -- modern SSDs will self-throttle if the temperature rises too high.  
Will a SAMSUNG 980 PRO SSD with Heatsink 2TB PCIe Gen 4 NVMe M.2 fit in my XPS 15 9560. That currently has a 1TB PCIe Gen 3 NVMe M.2 2280?
Will a SAMSUNG 980 PRO SSD with Heatsink 2TB PCIe Gen 4 NVMe M.2 fit in my XPS 
15 9560