The plastic tanks rust too. My 99 Tahoe came originally with a plastic tank. It started leaking. Found out they molded the little lock tabs that hold the sending unit, into the plastic of the tank. This steel ring molded in the plastic around the sending unit hole rusted. The rust swelled the plastic up around the hole and deformed it where it would not seal. At the time I could not get a new plastic tank so I went with a metal one that was for a 2dr. That was a lot of work but I got it.
The best tanks are the ones from Spectra in Canada. They are who made the OEM tanks. They have that nice tin coating, they are not painted. But with all this trade war stuff, not sure you can get one, especially if inventory dries up.