Building a Retro Gaming Setup with Raspberry Pi
I'd recommend RetroPie with a 32-64GB USB stick.
For controller, a xbox One Bluetooth one is optimal.
To get the roms organized, stick in the usb stick and run the usb-script (https://retropie.org.uk/docs/Running-ROMs-from-a-USB-drive/)
now you can load all your roms.
If you connect it to the internet you can also update all the emulators through the "Retropie setup" option.
the Rpi4 takes micro-HDMI -> HDMI, so your TV /Monitor will need a HDMI outlet.
also get a good enough usb C charger for the pi4, the official one would work.
Side-note, retropie uses launchbox so when you load your roms on the usb it will automatically load in launchbox and get organized by system.