But and however can often be used interchangeably But and however are often used interchangeably to mean ‘yet’, but they are punctuated differently because however in this context is a conjunctive adverb, (also known as an adverbial conjunct) not a conjunction. "Jim lost a fortune gambling, but he still lives in a mansion." "Jim lost a fortune gambling; however, he still lives in a mansion." or "Jim lost a fortune gambling. However, he still lives in a mansion." But is often regarded as more informal than however. Some people think you can’t use but at the beginning of a sentence. But you can. The Macquarie Dictionary (2005) says: ‘Some writers object to sentences beginning with but on the grounds that it is a conjunction which should link clauses within a sentence and should not appear to link a new sentence with the previous one. In fact many writers use but at the beginning of a sentence and there is no reason to object to the practice provided that it is not overdone.’ But and however have some distinct meanings of their own But means ‘on the contrary’ and ‘with the exception that’. "I like everyone but her." However can also be used to mean ‘by whatever means, condition or state’. "I will get there however I can." Reference: https://onlinewritingtraining.com.au/2017/03/07/but-and-however/

but is used more informally than however. both but and however are used to introduce a contrasting idea to something previously stated