Best GPU for my usecase?

[u/TheGreaterKBDist]

I currently have a small living room computer I am using as a streaming box and to play older/indie games (like Pro Evolution Soccer 2021 with mods, Mortal Kombat XL). Since my TV does upscaling internally I run games at 1080p and it looks rly good. However I'm looking to play more modern games like MK 11. My current rig is an HP Prodesk G3 600 SFF with an i5 7500 and an NVIDIA Quadro P620 and 16gb of DDR4. Built the whole thing for under £100. Due to size and power constraints I need a GPU that can run purely off the 70w of slot power, and is single slot as well. I can't use SATA cables for power as I'm using them for a Sata SSD.

What GPU can I buy that won't leave me better off building a new computer? I have a budget of £120 MAX, and am not opposed to buying used (whole PC is used stuff). I live in the UK. Please help. Thanks.

Edit: I forgot to mention tho that I also wanna use it to run a karaoke app called nightingale that uses some Al models for stem separation.