Generate passwords from your browser's cryptographic random source, with the character sets you choose and the entropy shown as you change them.
Around 80 bits for anything that matters and 60 as a floor. Entropy here is the length times the log of the alphabet, which is the honest measure for a random string, and it is why length beats adding symbols.
Taking a random byte modulo the alphabet length favours the first few characters, because 256 does not divide evenly. Bytes that would land in the uneven tail are thrown away here and drawn again.
It removes 0, O, 1, l, I and the quote marks. Worth it for anything read off a screen and typed by hand, and not worth the lost entropy for anything a password manager holds.
No. NIST dropped that advice years ago, because forced rotation pushes people towards a pattern with a number on the end. Change one when there is a reason: a breach, a shared device, a suspicion. Length and a manager do the rest.