Depends on what you want to do. ESP32-S3 devices are ridiculously cheap and come in a myriad of form factors. If you want a RP2040 form factor, they're like $5 each. They've got Bluetooth and WiFi built in, plus plenty of GPIOs.

If you need compute with a bit more horsepower, the myriad of NUCs or thin PCs exist. If you need both in a single board, then the myriad of other SBCs that aren't Raspberry Pi's...

a RPI is just a SBC with GPIO pinning (which isn't at all unique to RPI.).

The main reason it was/is the popular behemoth is not because of it's tinkerability, but because it got mainstream appeal and RaspianOS is polished enough for the average windows user to go "wow, neat."

THere is no "knock off pi", there are many many popular SBCs with the same performance at cheaper cost (O-Pi, arduino), not to mention the mini PC space (NUCS, ie intel asus.)

If you're a hobbyist, pick up some used thin clients from Ebay. I lost a couple of pis recently, and instead of replacing them, I bought a batch of Wyse 3040 thin clients for about $23 each, power supply (which is 12V) included. 2Gb RAM and a 4-core intel Atom - roughly equal to a Pi 4, but at (what is now) 1/3 the price.

if you're just trying to interface a bunch of pins to a usb port you can buy a pack of 3 USB-C ESP32s on amazon for like twenty bucks now.

Things get more expensive with specific ADC needs/etc