"and yet" is still surviving today in current English. What we call modern English is actually about 400 years old shortly after the sonnet was written. https://www.sparknotes.com/shakespeare/shakesonnets/section9/ "and yet" sometimes = the same as "yet" some people add the "and" some people do not in current English. https://grammarist.com/usage/and-yet/ -----, and yet at the start of a sentence is rhetorical shorthand, often followed by a comma and usually meaning, “That may be so, but…” And yet, by heaven, I think my love as rare "that may be so, (but) by heaven I think my love as rare." <- current English general meaning. "any yet" I believe is similar to todays "and yet" and fits the style of the poem any+yet. no matter,despite, regardless, etc.

Nevertheless. If Google Translate is correct, não obstante. It is a surprise reversal in the last two lines. He spends the first twelve saying that his girlfriend is not terribly beautiful. He does this by saying she doesn't live up to traditional comparisons. For example, it is considered attractive for a woman to have a slightly pink flush in her cheeks, as if she were blushing slightly. The conventional compliment is "she has roses in her cheeks." He says "I've seen roses. She doesn't have roses in her cheeks." Nor does she doesn't have eyes like the sun, or coral lips. And apparently she has bad breath! Then in the last two lines he turns around completely. He said "And yet;" he could also have said "Nevertheless," "But still," "Anyway," "Despite all this..." Despite her eyes, lips, cheeks, and breath, his love for her is just as strong as if she had eyes like the sun, coral lips, roses in her cheeks, etc. Be aware that Shakespeare's English is difficult even for native speakers to understand. We have to work at it and we need help with things. For one thing, it's poetry. For another, it's based on the culture and customs of 400 years ago. And finally, the English itself is old-fashioned.

And even so... And in spite of all this...