This fear is unfounded, the primary value proposition of .NET (FKA .NET Core) is that it's a high-performance cross-platform runtime that has first-class support for Linux.
It's been designed to be "cloud-ready" from the start where it's adopted a high-performance core with a leaner, modular runtime that supports side-by-side installations since Microsoft wants it to run well in the Cloud of which all cloud providers (inc. Azure) predominantly deploy to Linux VMs, whose trend will continue to dominate.
You can view the supported Linux distributions on their installation page which includes Linux binaries for x64, Arm32 + Arm64 including package managers for its supported Linux distributions (Alpine,CentOS,Debian,Fedora,openSUSE,RHEL,SLES,Ubuntu) [1]. As well as maintaining multiple Docker configurations for popular Distros [2].
With Linux now being a supported platform means if you have run into an issue you can report it where their full-time resources will resolve it. The old days of using .NET to push Windows is gone, the future is the cloud and Azure doesn't care if you run Linux or Windows VMs, it's all the same to them, they're still collecting rent for usage of their servers by the hour.
Not that Electron is appealing either but I get the draw fully.