Retirement tax questions

It seems the deadline for 2023 solo 401k is also in April 2024. If I do roth solo 401K, is the limit the same as the traditional solo 401k - For 2023, if I contribute all net profit of my LLC into roth 401k, the employer match will be $0? Is it true that the employer contributions must be made to a traditional solo 401(k) account, no roth?

 

Does the employee contribution have to be paid from the business bank account (no personal bank account)? 

 

On top of 401k roth contribution, I can also contribute an additional $6500 to individual roth ira if meet the AGI requirement?