Kudos for getting this done!
Sad that free BIOSes are so far behind modern hardware, but this is very necessary work.
i don't think it's really "far behind", it just can't run on hardwares that require manufacturer keys (e.g. intel bootguard)
afaik all modern x86 chromebooks ship with coreboot based firmware
You can get much more modern hardware with firmware. This was mostly an expirement to see how good LLM are at reverse engineering. Given that it went well I think making fully free (without Intel) x86-side firmware is possible.