Is an RS focused build viable in endgame?

I've wanted to make a Demon Form RS Infernalist because the theme is super cool but now, in act 5, RS damage is extremely low. I clear ok with fire spells but rares and bosses take quite awhile. I'm mostly built for minion damage and RS is just not holding up.

I just can't seem to build high ST damage into RS and fire spells. I'm worried it's not going to get better in endgame and I'd rather not waste time with it if so.

My build has 5 T3-5 +dmg mods across rings and gloves because that increases RS attack damage based on their stat page. I've found literally 0 +minion mods so that might be the biggest problem. I also run fire exposure.

Passive allocation is mostly minion damage, fire damage/resist pen, and ES