This is great! I did something very similar using AutoHotKey and Synergy : https://moshen.net/posts/virtual_kvm/
I worked for Symless for 2 years and I can tell you first hand that the owner had little interest in fixing or improving the core functionality, the code for which has remained largely unchanged for 12-15 years.
Most of the input bugs in the software are a decade old, and unless a community patch comes along that can be merged, the owner only has interest in keeping it working on new OS versions, and tarting up the UI/UX to support Symless as a lifestyle business.
In the 2 years since I left I've seen exactly 3 bugfix releases, one of which broke TLS, and none of which seemed to contain any significant original work.
Supposedly Synergy 3 is in the works, after Synergy 2 (which I worked on) was scrapped, but this will almost certainly only be a proprietary Electron UI for the FOSS CLI instead of a Qt/QML UI for the FOSS CLI (as v2 was).
Major versions of Input Director (v2.0) and ShareMouse (v5.0) have been announced in the last few months, and it looks like significant work has taken place on both projects. Both of these products need better marketing.
Unfortunately none of the alternatives to Barrier/Synergy seem to want to support Linux, which remains its moat. The days for that are numbered due to Wayland though (Synergy uses the X11 XTest extension to inject input).
[0] https://github.com/debauchee/barrier