Use Chrome or Edge on desktop and connect the display via USB.
Which variant do I have? The two 2.8" boards look identical and the silkscreen doesn't name the panel controller. The USB port count is a hint, not a rule: 1 port (Micro-USB only) is usually ILI9341 and 2 ports (USB-C + Micro-USB) is usually ST7789 — but 2-port boards fitted with an ILI9341 do exist, so the count can be wrong. Guessing wrong costs nothing but a re-flash: the wrong build leaves the backlight on with a blank, garbled or wrong-coloured image, and it cannot damage the board. Start with the build matching your port count; if the picture is wrong or never appears, flash the other one — that is the answer, not a fault in your wiring or your MiSTer.
Capacitive or resistive? You usually can't tell from the board — both 3.5" variants use the same display and PCB, and the touch chips present don't reliably indicate the variant. It doesn't matter if you pick wrong: the picture is identical either way, and the only symptom of the wrong build is an unresponsive touchscreen — if touch doesn't work, just flash the other one. (Hint: capacitive reacts to a light finger touch; resistive needs a firm press or a stylus.)
These official binaries are for personal use: they embed the project's private ScreenScraper credentials and may not be resold pre-flashed on hardware. Commercial builds must be compiled from source with your own credentials. Source code is free software — GPL-3.0 (firmware) and AGPL-3.0 (server); see LICENSE and TRADEMARK.md.