H4 EAD Suggestion

" I have an H1B active with my current employer until March 31, 2023 and recently my H1B transfer for another employer was also approved by USCIS until Jan 24, 2024. However I haven’t yet resigned from my current employer and plan to do so in the next 1 or 2 weeks. My wife’s H4 got approved with my current employer until March 31, 2023 today and I want to file her [H4 EAD]. Also my new employer has filed her H4 but it’s still pending. What are my options to file for her H4 EAD and approximately in how much time will the EAD arrive? Can I file her H4 EAD asap using my new recent H1B petition but ask for validity only until March 31, 2023?"