Can I use Private Key + NodeJS to make payments, without metamask or any other wallet

i want to automate some DApp websites, but they require to login with metamask everytime
is there any way to pay with privated key, insted of using metamask for payment everytime
Is it possible ?

you can get an idea on how to do it from this post: How to solve Returned error: only replay-protected (EIP-155) transactions allowed over RPC?

Thanks for sharing this info this is useful keep it up.