Generic x86_64 systems are supported using the limine boot protocol, any limine compliant bootloader will be able to boot it just fine. Options exist for UEFI and BIOS, our recommendation is Limine, which supports both.
No requirements for specific SIMD extensions are made apart from what x86_64 features architecturally. Both 5 level and 4 level paging are supported, with the system defaulting to 5 level paging if available.