Walaikum-as-Salam,
I'm assuming you are already on NVMe system/game drive since that's the biggest visible performance boost people notice when upgrading.
Upgrading from i7 4790 & 1080Ti on an HP LP3065 (2560 x 1600 @ 60 Hz) to either a CPU upgrade or a GPU upgrade would not gain you a lot of visible performance boost NOW, on the same monitor, except giving your system some longevity and making it future proof. If you want to go that route and upgrade your monitor in future as well then it makes sense to upgrade components one by one as and when budget becomes available.
In that sense I would suggest that you go AMD route rather than intel, since going with AMD's AM4 socket (e.g., B550) will open up more CPU options and upgrade routes. Intel's Z590 platform is a burning ship that intel will itself abandon with next CPU launch, these were meant for 14nm 11th gen CPUs alone and do not have any future, not to mention AMD has better IPC and Process Node.
B550 motherboards on the other hand support 3000 & 5000 series, but you can go with used B450 or X470 boards and run ANY AM4 CPU from 1000 to 5000 series.
AMD Socket AM4 Motherboard Chipset Solutions
| AMD Athlon™ Processors with Radeon Graphics | AMD Ryzen™ 1000 Series Processors | AMD Ryzen™ 2000 Series Processors with Radeon™ Graphics | AMD Ryzen™ 2000 Series Processors | AMD Ryzen™ 3000 Series Processors with Radeon™ Graphics | AMD Ryzen™ 3000 Series Processors | AMD Ryzen™ 5000 Series Processors |
| Compatible with | Compatible with | Compatible with | Compatible with | Compatible with | Compatible with | Compatible with |
X570 | X | X | X | ✓ | ✓ | ✓ | ✓ |
B550 | X | X | X | X | X | ✓ | ✓ |
A520 | X | X | X | X | X | ✓ | ✓ |
X470 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | Selective Beta BIOS update needed |
B450 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | Selective Beta BIOS update needed |
X370 | X | ✓ | ✓ | ✓ | ✓ | Selective Beta BIOS update needed | X |
B350 | X | ✓ | ✓ | ✓ | ✓ | Selective Beta BIOS update needed | X |
A320 | ✓ | ✓ | ✓ | ✓ | ✓ | X | X |
On the GPU side of things, it's pretty simple, 3070Ti is a very potent card, it's just the matter of current prices, and it's not gonna come down very soon, as GDDR6x shortages are also driving GPU shortages.
I would upgrade the CPU first, then in next installment will upgrade the GPU, maybe prices would be better by then or better cards (bigger VRAMs), then will upgrade the monitor. Ofcourse, CPU upgrade would necessitate motherboard and RAM upgrade. Go for 5600X setup.
CPU: 5600X with stock cooler
Mobo: B550 motherboard, ASUS/Gigabyte/Asrock have good reliable motherboards, mATX (Micro ATX) are cheaper than ATX, buy the one that is available and cheaper among the above mentioned brands, if you need WiFi then get a motherboard with built-in WiFi.
RAM: 16GB (2x8GB Dual Channel kit), 3600Mhz at CAS Latency ~14 / 16 depending on price. G.Skills Trident Z Neo is a good RAM for Ryzen but buy what is cheapest among above specs, speed and latency is more important than colour or RGB, look for speed 3600Mhz and a CAS Latency of C16 or lower.
SSD: NVMe SSD at least 512GB for your system drive, ~3000Mb/s Read/Write, 970 EVO Plus or 980 equivalent.
PSU: Get at least a 80+ Gold rated power supply, will save you in electricity costs in long term. Power draw for a RTX 3070 Ti is 290 Watts and PSU should be 750 watts or higher, don't skimp on PSU, cheap PSU will damage your hardware, get Corsair RM series or equivalent.
if you ever upgrade your casing, emphasize on AirFlow rather than looks or RGB. AirFlow matters a LOT. Get a case with good airflow. At a lower price point
Antec NX800 or higher budget Cooler Master H500M.