Best PC upgrade parts for $500?

Hey everyone. I'm looking to upgrade my rig and need some help picking out new parts.

It's been a minute since I was last deep into PC building—my current setup shows that—so I could really use some guidance on what actually holds up these days.
Basically, I need a CPU, motherboard, RAM, a CPU cooler, and maybe a new PSU too.

Here’s what I'm running right now:

XFX Pro 450w

NVIDIA GeForce GTX 1650

8gb Corsair vengeance ddr3

some old ASUS motherboard

Crucial MX500 500gb ssd

500gb hdd

NVIDIA Radeon RX 580 8GB

I'm aiming for an Intel build.

I'll shop at any major retailer where I can pay with a credit card via installments or just use cash on delivery. My budget is $1167

If you're dead set on buying right now and specifically want Intel in this budget, the Core i5-10400 is really your only logical move. Prices aren't great at the moment, but at least Best Buy carries it if you want to pay with a card or cash.
Personally, I’d just wait until the Core i5-12400 drops in early 2021 and hits roughly $667 (for cash, maybe slightly more on a card at Best Buy). If you grab that along with a decent motherboard and some RAM, you'll land right around your current budget. It's a much sharper processor—the 5600X is basically keeping up with the top-tier Intel chips right now.

https://www.bestbuy.com/processor-intel...m_medium=click

You don't strictly need an aftermarket cooler unless you're planning to overclock. For a light OC—which isn't even worth the effort most of the time—this one is fine. https://www.bestbuy.com/cooler-lc-co...m_medium=click

Otherwise, you could always go with an LC-CC-120 or a Freezer 34.

A B450 Steel Legend or a B450 Tomahawk Max are safe bets, though you might find better value elsewhere. Check PCPartPicker to see what fits your needs best.

The power supply should be fine, unless you've been absolutely punishing it with constant overclocking.

B550 motherboards have dropped in price lately, which makes me think high-end B450 boards are starting to lose their edge. Honestly, a mid-range B550 is basically on par with a premium B450 when you look at the VRM quality.

https://www.amazon.com/s?k=B550m+aorus+elite
https://www.amazon.com/s?k=asus+b550+pro4

I was originally looking at getting a Core i5-10400, but I was pretty lost when it came to picking a motherboard since I didn't really know what was actually worth buying. From what I can tell though, the B550 seems like a solid choice.
As for a cooler, if one comes included in the box, I don't think I need anything extra right now.
The only other thing I'm wondering about is whether my current power supply can handle this build, and if not, what would you guys suggest I pick up?

It’s plenty; an EVGA 450 W is a perfectly fine PSU. At the end of the day, your CPU will likely pull even less power than what you're running now, and your future GPU probably will too.