Alex done his job, New 4k TV on the way...
I don't think *I* did the job, more the picture set at low exposure showing just how much colour intensity the OLEDs can provide did... (Well...maybe that and the deal I found)
Honestly, after getting used to a similar Sony to what you have, and then adjusting things appropriately you'll be blown away by the increased colour depth, and movement clarity. And I really liked my old Sony, but the OLED is on another level once configured properly, ESPECIALLY for space stuff or anything with lots of black and pin pricks of light etc
Now you just need the AMP and uprated HDMI cables

(Zeskit Maya, KabelDirekt/CableDirect etc off the forest should work, just look for decent, HDMI 2.1b certified cables).
Don't spend crazy, 4K60 isn't that hard these days. 4K120+HDR is much more demanding so need to get decent quality cables or you'll get drop outs/negotiation errors.
The OLED will do 4K144Hz with the right cable if you plug the PC in too and set everything up right
Edit: FWIW, the HDMI cable that comes in the Series X, PS5 Pro and Nintendo Switch 2 boxes are good for the job, but they're not very long. Try to stick to as short as possible for HDMI2.1 (High refresh, high res).
You'll need a good one between the AMP and the TV at the least.
Decent ones are around £10-15, so not like you need to spend £50, just don't buy the £5 rubbish as that'll likely not be good for full bandwidth, stick with certified for a bit of extra chance they'll be good.
Certified ones should have a QR code on the packaging you can scan to verify they're a manufacturer/line that has been certified by the HDMI board.
Again, a bit of a PITA, and not a guarantee, but it becomes more of a lottery if aiming for full 4K120+HDR, and you want to aim for ones that have higher chance of not failing to keep up, given the price difference is relatively minimal.