I think your options are mainly virtualization or something like this
Virtualization is definitely easiest though; there's a transmission docker image out there that's preconfigured for a ton of VPN providers, including mullvad. It can be touchy to get working but is amazing when it does work.
A good frame of reference would be the VPS that lemmy.world is running on imo. Looks like they upgraded to a 4 core/16gb setup to handle the influx of users, so if your instance is running under 1k users, I believe those specs would be sufficient.
If it starts chugging, I wonder how well it'd work to run the server on the laptop and the DB on a VPS (or vice versa).
It says at the bottom you're using a version built in Nov 2021, you might just need to update to the latest release (latest Arch release is 4.23-1, built 10-29-2023).
If the version in your repos is that out of date though (you didn't state your distro so there's no telling offhand), your best bet may to be to build it from source and install it.