From a Linux command line it would be the command called arp, you need to add a static arp entry. I don’t know how that works on sense, but on Linux it would be something like
arp -s IP MAC
Maybe there’s a module in opnsense to help. The way I’ve done this before is using a machine connected to the same network at my target to wake up by logging into that machine and issuing the wake command.
WoL packets are usually sent to the ip broadcast address for the network as they’re not ip based. I don’t know if this would ever work well across networks. Can you do send the wol packet from the opnsense router instead? Does it work then?
If you’re sending it to the IP of the server, it likely works soon after your turn the machine off because the ARP entry hasn’t timed out yet, but once it times out it won’t work anymore. The router doesn’t know how to get to the machine. You may be able to add a static arp mapping to get it to work long term.
Is JellyFin listening on localhost? Try changing its binding to 0.0.0.0 instead. Localhost is not available off the local machine, so I’m not sure what you mean by ‘let devices from local host access the pc’.
I haven’t seen any business VOIP plans that are unlimited outbound, and no matter who you use you’re paying for calls to/from the PSTN. I use CallCentric - they have plans for 120/500/1000/2500 minutes to US/Canada. You need to pay for the line and e911 service, and yes they give you instructions on how to connect to many devices.
I think your total would be $40 or so per month for the line (unlimited inbound) and 2500 outbound minutes.
I’m not sure how consistent it is but the static binaries I have for btrfs-progs are about 2x larger than their dynamic counterparts. If you statically compile it only the functions actually used are included in the binary, so it really depends on how much of the library is used.
The phone or browser may be using DNS over HTTP (aka DoH), check if you can disable it for the wifi network. You may have to disable it on the phone or browser to get your desired behaviour - look up directions for your browser.