>>I've heard that PCs with native serial ports are now considered "professional" equipment
I mean, laptops, sure. But PCs I think most still have a COM port. I bought a "gaming" X570 motherboard recently and there's still a COM header on it, I'd need to buy the port itself but the mobo does support it natively.
Microsoft started an initiative in the late 90s to abolish "legacy" ports from PCs including serial, parallel, and PS/2. RS232 is not something you can expect on consumer-grade equipment.
I mean, laptops, sure. But PCs I think most still have a COM port. I bought a "gaming" X570 motherboard recently and there's still a COM header on it, I'd need to buy the port itself but the mobo does support it natively.