Not sure what your sources are, but I do believe the current vaccines - all of them available in EU - are still highly effective against all known variants, including SA and Indian.
https://www.medpagetoday.com/meetingcoverage/ats/92618
Also not really sure why you're so opposed to the AZ vaccine. And I certainly wouldn't recommend switching vaccines after your first dose, I haven't heard anything that suggests that's a good idea or recommended anywhere.
Do you have something I can review in regards to that?