Yeah - especially with nostr. At home I turn cell data off & shut down the VPN on my phone since it's using the wifi. When I go out & realize I have no data, I switch on the VPN & then enable cell data. Running the VPN on the phone & router slows performance. I'm pretty sure this is mainly the software running on the phone. Running the VPN on the router was significantly faster than running a software VPN on a PC.