CPU: Are you going to be doing a lot of media encoding/transcoding, or want to hang onto this rig for as long as possible before upgrading again? If so, get this CPU for $515: https://www.scorptec.com.au/product/CPU/AMD-Socket-AM4/77564-100-100000071BOX
otherwise, get this for $315 https://www.scorptec.com.au/product/CPU/AMD-Socket-AM4/77560-100-100000031BOX
RAM: Consider whether you really need 32gb - if you're just gaming or other light workloads, you won't need more than 16gb, and pricing becomes much better. If you do need 32gb, I'd recommend this kit for $280: https://www.pccasegear.com/products/47633, otherwise if you can settle for 16gb I'd get this at $160: https://www.amazon.com.au/dp/B07X8DVDZZ
Motherboard: If you want all 8 SATA drives to be connected directly to the motherboard no hassle, get this: https://www.scorptec.com.au/product/Motherboards/AMD-Socket-AM4/77670-TUF-GAMING-X570-PLUS-(WI-FI) (though you can find it for ~$50 cheaper on Amazon au).
If you want to save more, you can buy this board for $160 (https://www.scorptec.com.au/product/Motherboards/AMD-Socket-AM4/78473-B450-GAMING-PLUS-MAX) which has 6 SATA ports, then combine it with this 2 SATA port expansion card for $80 (https://www.scorptec.com.au/product/Controllers/SATA-&-SAS-&-M.2/64478-SST-ECS03), which saves you about $100 total over the other board.
SSD: I'd recommend getting an m.2 NVMe drive given how many SATA drives you're going to have, getting an m.2 NVMe drive means you're not cutting into the number of SATA drives you can have. I'd recommend this at $100: https://au.pcpartpicker.com/product/XML48d/silicon-power-a80-512-gb-m2-2280-solid-state-drive-sp512gbp34a80m28, or the 1tb model for ~$180. Note: turns out that using an m.2 drive on any motherboard will mean that two SATA ports are disabled, so you'd actually be better off getting a SATA SSD like this for $90 instead if you wanted maximum storage: https://www.scorptec.com.au/product/Hard-Drives-&-SSDs/SSD-2.5-&-PCI-Express/71046-CT500MX500SSD1
PSU: What you've chosen is fine
Case: What you've chosen is fine
Drives: I'd recommend this drive for the best price/GB over 10tb for ~$500 after shipping - https://www.newegg.com/global/au-en/seagate-exos-x14-enterprise-st12000nm0008-12tb/p/1Z4-002P-00JV2. If you don't want to spend so much per drive, but lose some density in terms of the maximum TB amount you can fit in your case, I'd recommend this for $310 - https://www.shoppingexpress.com.au/buy/seagate-ironwolf-8tb-7200-rpm-3.5-sata-nas-interna/ST8000VN004