different setup per client

[mldz]

L.S.

hi all. I'm new to OpenVPN and have played around with it a bit. I have installed it on a Raspberry Pi 4.
Some questions, if I may;

1) is it possible to setup OpenVPN in a way that client A uses the PiHole DNS and client B uses it's own DNS server? Now all clients use the PiHole, which is not preferred.
# Set your primary domain name server address for clients
push "dhcp-option DNS 10.8.0.1"
push "block-outside-dns"
(First remark: I think I've got that covert by adding push "dhcp-option DNS 8.8.8.8" to the clients file in the /etc/openvpn/ccd folder. Is this the correct approach or is this pure luck.
Second remark: https://serverfault.com/a/826473/90274 ==>
"As of 2017 (OpenVPN 2.4) this is now possible. Add this line to your client config file:
pull-filter ignore 'dhcp-option DNS'")

2) all clients now use the internet connections of the server, to get the actual data. For client X I need that, but I would like client Y to be able to use the network (go to computers and use the PiHole), but client Y should use it's own internet connection to download data.

3) I have a fast internet connection at home (500Mb). The ethernet connection which is used for the raspberry Pi is able to get to that speed. Speed tests on the raspberry Pi have shown speeds between 250-400Mb. However, when I use openVPN, the max download speed on the client computer is about 65-70 Mbit (this is measured within the same network. With fast(er) Wifi / Ethernet available). I have read this page: https://community.openvpn.net/openvpn/w ... orks_Linux and tried to tweak the setup file. But it does not seem to have any upward effect. Anyone installed OpenVPN on a raspberry Pi4 whom had better results? if so, could you share your server setup conf file and you client setup?
thanks in advance!

Matthijs