Problem Updating to WP version 5.9 with Astra theme

Hi
I haven’t been working on a site for a while and now client would like to go ahead with getting things updated. I’m currently using WP 5.6.7 and want to update to 5.9.
However when I did this and tried to log back into WP admin I get a page that says critical error. I just want to know if this may be a theme issue. I’m at my wits end and can’t figure it out. I have restored site to a version in January 2022 but cannot move forward. Any suggestions.