Your partner has the right to live and work in the UK, and to travel in and out of it without a UK visa. This brexit mess does not abridge any of those rights.

1. If you guys are married, she can apply for the EU Settlement Scheme[1].

2. If you guys are not married, you need to first register a civil partnership[2], and then she can apply for the EU Settlement Scheme.

None of these require EU citizenship for your partner.

[1] https://www.gov.uk/settled-status-eu-citizens-families/apply...

[2] https://www.citizensadvice.org.uk/family/living-together-mar...