My understanding is you cannot apply for a FP from within UK. It is primarily an entry visa.
If you go back to home country you will have an address there, even only for a short time.
You can explain special circumstances in a cogent cover letter if you wish.
It's not that HO specifically
disallow partners applying for a RC to work, they just do not issue a COA that
confirms the right to work.
Its up to an employer to take you on (or to continue to employ you), with or without a COA showing a right to work.
fyi, an interesting take on these challenges:
https://www.freemovement.org.uk/sponsor ... dismissal/