You obviously have absolutely no idea how it works lol, having 2 systems or even more doesn't affect the performance at all
Many gaming companies are removing MAC support just because the number of MAC gamers is miniscule compared to PC and Console gamers. It's understandable too. Why spend money on the least profitable platform when you can use your resources in more profitable areas and make even more money.
My Lenovo IdeaPad (originally supposed to be a computer for my college classes) can run beamng just fine, I mean it doesn't in anyway compete with other dedicated PCs in terms of graphics abilities, but I bought a 500GB SSD and an 8GB VRAM upgrade at a later date, and can run most maps. The only downside is that it's running a dedicated Intel GPU. --- Post updated --- In total, the entire build so far is under $400 USD.