I don't want PCs to be like smartphones. I don't want locked bootloaders.
I'm sorry to burst your bubble, but since Microsoft made TPM mandatory for Windows 11+, locked down bootloader are on their way.
Basically, TPM allows (Windows) software to validate/verify the integrity of the OS and hardware. This also (could) include the bootloader/bios if Microsoft chooses to do so.
TPM is the equivalent of attestation on Android, which is the exact reason why your Banking App won't work on your rooted/custom Android Phone.
That being said, we should embrace ARM. X86/AMD has 30+ years worth of "history" baked into each ( CISC) chip. This complexity is why your PC draws soooo much power and generates soooo much heat.
Yeah, but RISC-V also costs 1/10th the price of a Pi.