Question regarding the future of Mac OS / 64-bit and ARM64 support

Since macOS Catalina has decided to drop 32-bit support, OpenBVE has been unable to run on Macs without utilizing virtualization software (e.g. VMWare Fusion / VirtualBox / Parallels Dekstop; while OpenBVE functions properly, there is considerable performance penalty) or dual-booting into a compatible operating system (i.e. Windows / Linux distros; native support is offered, though rebooting between systems may be cumbersome);

this on-going incompatibility is compounded by Apple's transition to the ARM64 architecture, where x86 coding is likely unable to be executed on ARM-based Macs natively (lest Mono has an ARM64 build), while has x86 emulation via virtualization options (via Parallels Desktop) is still uncharted waters, with no guarantee on decent 3D performance for the supported guest operating system(s).

Given how BVE Trainsim has jumped to 64-bit from 6.0 onwards,  would it be possible to fork a 64-bit branch that offers support to ARM64 / x86-64 for operating systems that cannot execute 32-bit applications? While it may be niche, it would be interesting to have an ARM64 branch that can operate on both Windows 10 for ARM and future macOS releases (and even iOS / iPadOS, given the recent unification).

At a rough guess, we're about 40- 50% of the way there. 
Unfortunately, the rest of the task is the hard part!

Most of the main code is platform agnostic.
However, text drawing and some other smaller parts of the renderer are still using GL1.2 
This is easier to sort, and will be done at some stage.

The big problem is the main menu. This is a hugely complex Windows Form & there is simply no working 64-bit / ARM implementation for that at the minute.

Progress will be made, but please don't expect anything soon.