Comment by ZiiS

https://github.com/x653/xv6-riscv-fpga is a fully open RISC-V core, using fully open tools written to tiny FPGA. It betters 386 performance, is practical for an individual to recreate, and it is almost inconceivable that the underlying hardware could have compromised this usage. If your security posture cares about ME et al. you also shouldn't be running any form of speculation, so 'modern' performance would be off the table even if you bought Nvidia and TSMC. I would more judge a concerted effort comparable to larger open source projects could design verifiable hardware for processes that it readily available to crowdfunded projects that are more efficient and performant then anything released in the previous millennium.