In terms of gaming x3(120ghz refresh rate means you are guaranteed stable 60 fps minimum - assuming stable ang game). Note9pro only goes up to 60ghz(I think it says it goes to 90ghz,tho?) so expect some silhouette if games decided to drop frames.
In terms of music it depends x3 has a stereo speaker using the bottom speaker and the smaller phone speaker near the camera. Note9pro only only has monaural with vibrato tech that I can't be bothered to explain.
Wierdly, tho if you are using it for regular internet surfing the Note9pro actually loads in and out of apps faster by a about 22 seconds. So king mahilig Kang magtiktok and mag Facebook medyo hindu nag hahang so Note9pro.
wala akong masasabi in term of photo and video since halos the same Lang naman Yan in the end, if Mas bright si poco and Mas contrast si note 9pro. PAREHO LANG SILANG BUGOK PAG NIGHTMODE MA NG PINAGUUSAPAN.
Tldr, note 9pro is cheaper(11990php) but if you can find poco in a sale(regular price nanG 6gb/128gb poco 12990php ung cheapest na nakita ko) then spring for the poco, tatagal siya for at least until 2022 tapos Palit phone ulit. Guhehehe...