not to be rude, but; excuse the phrasing, but
A set phrase used to soften a potentially blunt or critical statement. It acknowledges that the following words may sound harsh.
Not to be rude, but that plan isn't realistic.
Excuse the phrasing, but his explanation was hard to understand.
Means 'frankly speaking' and is more direct, without the built-in apology for harsh wording.
A fixed phrase composed of 言い方 (way of speaking), は (topic marker), 悪い (bad), and ですが (but it is). The expression literally means 'my way of saying it is bad, but...' and serves as a conventional hedge.