Do like Xenia does and get a thinkpad. My main computer is a $200 refurb thinkpad from eBay. They are known for good Linux support and because they are popular there is a big online community in case of trouble.
But your existing apple hardware can last a long time with Linux. Unlike Mac os it isn't designed to get shitty after a few years to encourage buying a new one. I also have a 10+ years old Mac mini as a secondary computer and it runs decently with Debian.
Sounds like it's growing pains of an organization which used to be small and informally managed bumping the limits of that.
Its never a bad time to (re)read the tyranny of structurrelessnes.