Buildapc

Good start. Here's the things I noticed:

1. You don't have a GPU. The CPU you selected doesn't have an iGPU, so you'll need to have a dedicated GPU for the computer to work. Otherwise, you'll want a CPU with an iGPU. I believe you can get a 5600G for roughly the same price. Its CPU power will be slightly weaker than a 5600, but it'll come with an iGPU, and for $20 less cost. And it should be compatible with the rest of your build.
2. BIOS shouldn't be an issue. Older models of motherboards come pre-flashed with the compatible BIOS now. You only have to worry about flashing the BIOS if your particular motherboard was manufactured before the CPU came out (since the manufacturer obviously wouldn't have been able to flash the BIOS for a then-nonexistent CPU). The actual process of flashing a BIOS is really easy, but you'll need to install a compatible CPU first to flash the BIOS. Just follow the instructions on the motherboard manufacturer's website (or manual). It's pretty idiot-proofed
3. You'll want to buy speakers or headphones. Modern computers don't really need sound cards unless you're doing audio work, but you'll still need a way to hear the audio. (You'll also want a mouse, if you don't already have one)
4. 8 GB RAM is really not enough these days, even if you're using Linux. 16 GB is really the lowest acceptable amount nowadays. Doubly so because DDR4 RAM nowadays is really cheap. For just 20 dollars more, you should get 16 GB, DDR4-3200. It'll save you a ton of headache later.
5. You should get an SSD. SSD's are getting cheaper. Granted, hard drives are still cheaper, but it's getting to the point where the increased speed of an SSD easily offsets the increased cost of an SSD. SSD's significantly improve things like time it takes to boot up, time to open video or picture files, time to open programs, etc. It's really kind of a no-brainer nowadays, even if you don't game. I would not recommend a hard drive-only build nowadays, simply because the performance-per-cost is no longer viable. You should either do a full SSD build (more expensive) or an SSD+HDD combo (less expensive, but requires you to know where to put files). I would probably recommend getting a 1 TB SATA SSD (Samsung 870 EVO, $40) and a 1 TB HDD (WD Blue 3.5" 1 TB 7200 rpm, $30). This combo should get you the same total storage space, but it'll be much faster, and for just $10 more. Alternatively, you can consider if you even need 2 TB in total, and just get a 1 TB SSD. A solid 1 TB NVMe SSD goes for $60 nowadays.
6. Have you tried using that keyboard before? My personal experience with membrane keyboards has been generally negative. They feel really mushy and they cause a lot of typos because you need to press all the way down for an input to register. Perhaps it's not an issue at your current price tier, but I would recommend at least considering a mechanical keyboard. Despite all the stereotypes about mechanical keyboards being loud, there are many types that are designed to be quiet, and many more that are designed to do all sorts of things. I personally can't stand the clacking, so I use a mechanical keyboard with red switches (quiet). Keychron sells high-quality mechanical keyboards for relatively cheap. I would recommending giving their catalogue a browse.