Based on your advice above, I requested quotes from a few providers. Of course - they have put their twist on the request - but cost over four quotes varies by 1k. Systems are below. Any advice as to what would be the better choice / changes etc.
System 1
CPU: AMD Ryzen 9 3900X 12 Core Socket AM4 3.8GHz CPU Processor + Wraith Prism
CPU Cooler: Noctua NH-D14 Multi Socket CPU Cooler
Motherboard: Gigabyte X570 AORUS PRO WIFI AM4 ATX Motherboard
Memory: Corsair Vengeance LPX 32GB (2x 16GB) DDR4 3200MHz
Storage: Intel 660p 1TB M.2 PCIe NVMe 3.0 x4 3D2 SSD SSDPEKNW010T8X1
Video Card: Sapphire AMD Radeon RX 5700 XT 8GB Video Card
Case: Corsair Carbide 275Q Mid-Tower Quiet ATX Gaming Case - Black
Power Supply: EVGA SuperNOVA G3 750W 80 Plus Gold Fully Modular Power Supply
Operating System: Windows 10 Professional 64-bit OEM DVD
Total incl assembly and shipping: 3,118.92
System 2
CPU: AMD Ryzen 9 3900X (Base: 3.80GHz)
CPU Cooler: Noctua NH-D15 AM4 Special Edition CPU Cooler
Motherboard: Gigabyte GA-X570 Aorus Pro WiFi MB, X570,
Memory: G.Skill Fortis 32GB (2x16GB) PC4-19200 (2400MHz) DDR4, 15-15-15-39,
Storage: ADATA 1TB SSD, XPG SX6000 Pro, NVMe PCIe M.2 2280
Video Card: Gigabyte AORUS GeForce RTX 2080
Case: Corsair Carbide 275Q Mid Tower Black ATX Case
Power Supply: Corsair 650W RM650x (2018) Gold Power Supply, 80 PLUS Gold
Operating System: Microsoft Windows 10 Pro
Total incl assembly and shipping: 3,537
System 3
CPU: AMD Ryzen 9 3900X (Base: 3.80GHz)
CPU Cooler: Noctua NH-D15 AM4 Special Edition CPU Cooler
Motherboard: Gigabyte GA-X570 Aorus Pro WiFi MB, X570,
Memory: G.Skill Trident Z RGB 32GB (2x16GB), PC4-25600 (3200MHz)
Storage: Corsair 1TB SSD, MP600, M.2 NVMe PCIe Gen4
Video Card: ASUS Radeon VII (Base: 1400MHz, Boost: 1750MHz), 16GB
Case: Corsair Carbide 275Q Mid Tower Black ATX Case
Power Supply: Corsair 650W RM650x (2018) Gold Power Supply, 80 PLUS Gold
Operating System: Microsoft Windows 10 Pro
Total incl assembly and shipping: 3,961
System 4
CPU: AMD Ryzen 9 3900X (Base: 3.80GHz)
CPU Cooler: Noctua NH-D15 AM4 Special Edition CPU Cooler
Motherboard: Gigabyte GA-X570 Aorus Pro WiFi MB, X570,
Memory: G.Skill 3200Mhz Ripjaws V RAM PN F4-3200C16S-16GVK (2x16GB)
Storage: 1TB Samsung 970 Evo PLUS M.2 PCIe SSD PN MZ-V7S1T0BW
Video Card: Gigabyte RTX2080 8GB AORUS XTREME
Case: Corsair ATX Obsidian 500D Tempered Glass Case Black
Power Supply: 750 Watt Corsair RM750x 80 Plus Gold
Operating System: Microsoft Windows 10 Pro
Total incl assembly and shipping: 4,124