I've been trying to do 1T1R simulations through Ngspice and I keep getting errors. I think I am having some convergence issues. Has anyone had any luck doing these simulations, or can help identify what I might be doing wrong?

I got same issue and solved it by permutate reram_cell and mosfet. Indeed, I attached pmos upon the TE pin of the cell. This approach would solve your issue.

Okay, I'll give that a try thanks!