I would like to install Electrum Personal Server (or S or X?) on that same server (RHEL) then link to Sparrow Wallet (on windows 10 but same network) using Ledger Nano S (already set up).
Sparrow Wallet can be directly connected with Bitcoin Core[1]. It's using BWT which I think is almost the same as Electrum Personal Server. Is there any other reason why you want to install those Electrum servers?
[1]
https://sparrowwallet.com/docs/connect-node.htmlThat's only if the software runs on the same machine. But he said his Bitcoin Core install is on a server and I doubt he'll connect his hardware wallet to his server when he needs to do a transaction. That's where Electrum servers come in.
I'd recommend
electrs for low resource utilization and good performance:
https://github.com/romanz/electrsMy
own install guide for it is based on openSUSE (zypper package manager), but it's basically the same for other Linux distributions.
They also have their own install guide for Ubuntu with
apt:
https://github.com/romanz/electrs/blob/master/doc/install.md