There's some point u have to decide if u want to build a gaming pc
-First : how much budget cost u want to spend, the cost can decide which specification pc gaming u will got
-Second : there are tier class of gaming pc build, depend the part of pc like processor, gpu, motherboard, etc.
Example: High End Processor (intel core i7,i9. AMD Ryzen r7,r9 series)
High End Gpu (Nvidia Gtx 1080 series, Rtx 2000,3000 series. AMD rx 6000 series)
High End Motherboard chipset (AMD chipset X570, Intel Chipset z490,z390 )
Mid End Processor ( intel core i5. AMD Ryzen r5 series)
Mid End Gpu (Nvidia Gtx 1050,1060,1070,1650,1660, series. AMD rx 500 series, some of rx 5000 series)
Mid End Motherboard Chipset (AMD chipset b450. Intel Chipset b460, b365, b360)
Which tier pc part, u want to build
-Last : What game do you want to play, does it require high spec pc?
i suggest u best budget pc if u want to buying, u can build AMD Ryzen 5 Zen2 or 3 pair with Nvidia Gtx 1050,1060,1650,1660,series.
anyway, the best pc build rightnow is, AMD Ryzen 9 5900x or Intel Core i9-11900K pair with Nvidia RTX 3090 or AMD RX 6900xt