How do you feel about Anya Taylor-Joy as an example of regional and familial influences on accent? She's said that at this point she's so muddled up she generally just imitates whoever she's speaking to in English. (Also I don't speak Spanish but apparently hers has a very specific Argentinian accent.)
So I am super out of touch here and I had to look her up. Furthering my arguments that I really am just a giant nerd and please don't ever take what I say as coming from anyone who has the ability to act like a regular human being who has shame, I watch almost no TV. I've heard of The Queen's Gambit, but I haven't seen any of it and looking up her filmography I haven't seen a single dang thing she's in.
So I went ahead and pulled up her recent SNL monologue (another show I only watch when they do something someone wants an opinion about--had to get the Gen Z/AAVE sketch recently because I got a lot of questions about it and I hadn't seen it, of course). I listened to it a few times and took some notes on what I hear, but I didn't throw it into phonetic analysis software or anything.
Tiny primer: what you might think of as a vowel is not a vowel. If you're an English speaker, you probably learned in school that there are 5 vowels, A E I O U. And then you learned about "short" and "long" vowels, which have nothing to do with length and is all because it's hard to explain to a seven-year-old who is trying to learn to read that what they're producing is the high front lax vowel. Sidenote: if you really want to go crazy, that vowel /ÉŞ/ is the one we teach is "short I," but that vowel's tense counterpart /i/ is the vowel we teach as "long E." Yeah. It makes no sense. There are not five vowels in English. There are about sixteen, depending on the specific variety.
Because of this, phoneticians usually talk about vowels, especially English vowels in terms of the Wells' Lexical Set, a series of words that contain the vowel in question. That way, when we talk about the BATH vowel, we can investigate that speakers in England make one vowel and speakers in the US make a different vowel, but that bath, pass, and staff are going to use the same vowel in each English, even though the two Englishes are going to use a different same vowel.
Clear as mud? Let's make it even murkier.
So English doesn't have five vowels. But Spanish does: a e i o u, and they have a perfect one-to-one correspondence to their spellings. So when Taylor-Joy learned English in London, at age 8, she was probably putting the Spanish vowel system on English vowels. But then she very obviously learned a pretty prestige variety of London English, likely shooting for Received Pronunciation. And my guess is, these two things interacted in really interesting ways.
Offhandedly, I hear very RP influences on her THOUGHT and BATH vowels. Neither of these vowels exist in Spanish, so there was probably a hole for her to fill with the RP vowel. Meanwhile, her DRESS, STRUT, and LOT sound very...if not quite U.S. English, certainly not RP. LOT is in Spanish, STRUT and DRESS are not. Meanwhile, GOAT, which is in Spanish, is SUPER RP ("only new TV" at 1:29). She also has a very, very English /Éš/--it's the retroflex that is almost limited to English varieties, rather than the tap/trill version from the Spanishes.
So, she's got a lot going on. Some of it is language influence, some of it is regional, some of it is prestige. I also don't know enough about Argentine Spanish (aside from the cool pronunciation of /j/ as /Ę/ in a word like brillo) to comment on how her particular Spanish variety is affecting her English. But in short, my professional opinion is...
...her English is really, really cool. Thanks, anon, that was fun!