€2500–€3000 gaming PC build help

Hi,
I’m building a gaming PC with a budget around **€2500–€3000 (Denmark)** I mainly play competitive games like **CS2, Valorant and overwatch,** so my focus is high FPS, low latency and stable performance at 1080p stretched / low settings. I also want to be able to stream live without having any trouble with lag or slower gameplay.
I’ve found a mix of used and new parts (some only lightly used with receipts and remaining warranty):

CPU:
Ryzen 7 9800X3D (\~€320–€330 used, \~2 weeks old) (this one is maybe sold now)
Motherboard:
ASUS X870 board (\~€130–€150 used deal)
CPU cooler:
Arctic Liquid Freezer III 360 (\~€50 deal)
Case:
NZXT H7 Flow with extra f360rgb core and f120rgb duo (\~€120 used bundle)
PSU:
ASUS ROG Strix 1000W aura edition (\~€110 used, \~6 months old)

Storage options:
WD SN850X 1TB (\~€80 used deal)
WD SN850X 4TB NVMe (used \~2 months, \~€400–€430, warranty left)
Havent found a deal yet for 2tb

RAM options:
Corsair vengeance rgb 32GB DDR5 6000 CL30 (\~€400–€470)
or 64GB kit (\~€530–€550)

GPU options I’m considering:
Sapphire RX 9070 XT Nitro+ (\~€700)
RTX 5070 Ti (\~€800–€1000 depending model)
RTX 5080 (\~€1150–€1350)
RTX 5080 ROG Astral (\~€1500)

My questions:
For my use case (CS2 / Valorant / competitive FPS gaming), which GPU makes the most sense?
RX 9070 XT Nitro+
RTX 5070 Ti
RTX 5080 (standard)
RTX 5080 ROG Astral
Is there any real point going for a 5080 ROG Astral, or is it just wasted money for esports-focused gaming?
If I go for a 5080 build, would anything else need upgrading (PSU / cooling / CPU), or is the 9800X3D enough?
Any EU/Denmark marketplace suggestions besides eBay, DBA and Facebook Marketplace?
My main focus is high FPS, low latency and stable performance over time. I don’t really care about ultra settings or ray tracing.

Although once in a while I Will also play some story game, Watch movies or do some other stuff, but mainly fps gaming

Thanks a lot for any advice 🙏