im not too well versed in her accent over the years but from what i gather shes is scottish but learned to mask her voice to be more american a long time ago. How thick her natural accent really is can be up for debate, but if the average english speaker can understand her i dont think its faked much
shes been masking since at least early 2020, shes also a prime example of a chronically online individual, and its not uncommon for those types to naturally fall into a more 'americanized' accent over time. When you can speak a language and interact with a certain accent enough you start to adopt similar patterns. So she probably just kinda changed a bit over time, and being in front of a mic and speaking likely puts her into a certain mental state where her less natural accent is just habit