A much better CPU, SSD and power supply. With your budget it's pure insanity to go for a lower end part and a power supply that is three times more than what you need. The better option, as has been suggested, is getting the better quality 550W RMX as the entire system won't even go over 400W
PCPartPicker Part List: https://nz.pcpartpicker.com/list/gVr8Nq
CPU: AMD Ryzen 7 3700X 3.6 GHz 8-Core Processor ($544.00 @ 1stWave Technologies)
Motherboard: MSI MAG B550 TOMAHAWK ATX AM4 Motherboard ($345.00 @ 1stWave Technologies)
Memory: G.Skill Ripjaws V 16 GB (2 x 8 GB) DDR4-3600 CL16 Memory ($198.90 @ Newegg New Zealand)
Storage: ADATA XPG SX8200 Pro 1 TB M.2-2280 NVME Solid State Drive ($291.84 @ Aquila Technology)
Video Card: EVGA GeForce RTX 2080 SUPER 8 GB BLACK GAMING Video Card ($1424.80 @ Newegg New Zealand)
Case: Fractal Design Meshify C ATX Mid Tower Case ($195.00 @ 1stWave Technologies)
Power Supply: Corsair RMx (2018) 550 W 80+ Gold Certified Fully Modular ATX Power Supply ($195.00 @ 1stWave Technologies)
Case Fan: be quiet! SilentWings 3 High-Speed 77.57 CFM 140 mm Fan ($33.00 @ Mighty Ape)
Case Fan: be quiet! SilentWings 3 High-Speed 77.57 CFM 140 mm Fan ($33.00 @ Mighty Ape)
Monitor: Asus TUF Gaming VG27AQ 27.0" 2560x1440 165 Hz Monitor ($799.00 @ 1stWave Technologies)
Total: $4059.54
^ put a 2080S in there mostly for price referencing, but waiting for Ampere/RDNA2 would be the way to go.
I also put the Meshify C in the list since the H510 really isn't ideal for airflow, so unless you're absolutely set on keeping it for the build, then a Meshify C or Phanteks P300A/P400A would be better for cooling.
Also threw in the VG27AQ in there as a very solid 1440p 144Hz monitor, but the 27GL850-B picked by @Ed-petit is also a great choice.