I have switched everything to privacy alternatives is it safe to delete my Google account or is it needed for some android features also if I delete my account does Google delete all my data if not, can I request the deletion of my data under the GDPR
Google will eventually delete your data, eventually. You can request the gdpr deletion.
Depending on your phone, you might find life easier with Google account, but it doesn’t need to be your old Google account. It could be a throwaway. Mostly for Play store access. Other than that it’s not necessary
Before you delete your account, make sure you use Google takeout to get all of your data and archive it for your purposes