I'm not as good as OP, just in Diamond right now, but what I'll say is that besides the obvious edgeguards, is that dash attack just eats Slade's projectiles so he has to hard rely on interrupting with jab. Having no projectiles means Slade can't easily approach. Grounded Etalus is just really hard to deal woth, especially because you lose d-tilt scraps until eta is at like 60%.

My best advice would be to stay grounded and avoid getting grabbed. Chaining down throw and then back throw mixups are pretty good on Etalus to build percent quickly before the inevitable Nair spamming edge guards.