To answer your question: yes, you can plug your mics into a good 8-track recorder. BUT, you still won’t have as much control over the signal as you would with a mixer.
Good mixers have MORE and better control over adjusting the level. They have a trim AND a fader control; recorders and cameras do not (if they do, it’s usually menu driven). This can make a big difference with certain mics. Even Sound Devices, which makes maybe the best 8-track recorder, also makes two different kinds of mixers to go along with the recorder.
Don’t think that just setting the levels and leaving it will get you good audio. It takes constant adjusting and tweaking of the faders to achieve good results.
Best,
Dave J