Weird No Post Problem

Hi there! I just bought a new custom build PC, nothing fancy but enough to start enjoying some games on it, all was working fine until recently I started having troubles starting up my PC, I'm really new to custom computers and is kinda overwhelming how anything could be the problem when the computer doesn't start, been trying some things to troubleshoot the problem but I'm not having progress so far.

When I press the start button on my computer the fans and all the RGB lights on the ram, graphics card and CPU tower turn on, but the PC doesn't Post, no beeps or led sequences on the motherboard signaling a problem, its just stays like on an idle state, the lights on the CPU tower fans turn on rather dim and flickering, which I think is weird and got me to think was an issue with my power supply.

I found I workaround to get the PC starting and that is whet the things started getting weird, I noticed that my keyboard and probably my mouse too, are not detected when I turn on my computer, they also have RGB lights and none turns on, they are usually connected to the motherboard USB ports, so I have to unplug my keyboard and plug it to my CPU tower USB port, some times doesn't work at the first try so I unplugged it and re-plug it until the RGB lights on the keyboard stay on, then I press enter and Bingo, the computer starts.

Naturally I tough that maybe the motherboard had an issue with the peripherals, but I really didn't know not having a keyboard attached was enough to prevent my PC from starting, I updated the BIOS and kinda look for any configuration that could result on the problem but found none. before updating the bios I detached the motherboard CMOS battery to reset it.

I also tough maybe was some software configuration on windows, but the only thing I changed before it started happening was the fast startup, which seems kinda unrelated.

Any ideas what could cause the problem? , I have no clue but a slight suspicion that it could be something really easy...
anyways, if the post was longer than necessary and weirdly redacted I apologize as English is not my first language and I tried to be clear as possible.

Here is some information on my computer>

CPU Type OctalCore AMD Ryzen 7 1700, 3200 MHz (32 x 100)
Motherboard Name Asus ROG Strix B450-F Gaming (3 PCI-E x1, 3 PCI-E x16, 2 M.2, 4 DDR4 DIMM, Audio, Video, Gigabit LAN)
Motherboard Chipset AMD B450, AMD Taishan, AMD K17 IMC
BIOS Type AMI (12/09/2019)
Communication Port Puerto de comunicaciones (COM1)

Thanks for the help!