So many vague things that barely make sense...amateur indeed but you can learn! (How does one post 6,000 posts in this forum without becoming a 401(k) master? Pretty interesting.)
What was the money invested in when in the old Empower plan? (Doesn't matter any more but you will learn things in the process of figuring this out.)
What is the money invested in now in the new Vanguard plan?
Why can't you prove fees? They should be clearly listed in transaction history.
Why doesn't Empower have low-cost funds? I know plan admins (your HR department typically) can choose funds from what the 401(k) provider (Empower) offers, but there are some common ones that it would be surprising to not see. Most likely you have target date funds...0.04% expense ratio on those according to this:
https://www.empower.com/client/jpmc/enrollment/documents/investment_funds.pdf Those would be an OK starting point.
You cannot simply put the minimum in Empower and the rest in Vanguard, and hey you did allude to knowing this. Nice! The Empower contributions are going to be following 401(k) contribution rules/limits. The Vanguard contributions would be one of taxable/TradIRA/RothIRA depending on your qualifications and choice.
The in-service rollover comments by others seem accurate.