Do I miss out on anything by just buying my engineering items?

The current crafting system is absolute garbage, with more talent trees, component quality levels, cooldowns, regenerating resources, and other nonsense than actual items to craft. I want to avoid interacting with it if possible.

Can I just leave my engineering skill at 25 and buy goggles and tinkers off the AH? Do I miss out on anything by doing so? Is there even anything worth buying?

Tinkers you can buy - engineering goggles and bracers are BoP, but you can commission another engineer to make them for you using the craft order system.

If you’re not interested in putting in the time requirement to fill out the trees (which would allow you to either craft them yourself or craft the components cheaper than the AH), that’s fair enough, you can absolutely buy the mats off the AH and commission the items off someone who did all the grind. They’ll probably charge a fee, but if you don’t enjoy the processing of levelling the profession, you’ll probably find it a better deal.