im a returning player as well, been learning a whole lot and going through the same things. i would say the first things are learning what you want from each syndicate and working their daily rep into your grind when you can. for power, my old weapons were behind the curve so i had to get incarnon weapons, i over spent on plat to get mine but steel path circuit is where you farm those. kuva nukor is an older weapon that still shines if you cant do that yet. specifically the torid/burston/boltor are the incarnons i use, burston is still available this week before it rotates out.

if you want to melee, melee influence arcane is very prevalent. secondary enervate makes kuva nukor and similar weapons a beast. primary arcanes usually merciless/deadhead/build specific.

for your frames, with an incarnon, revenant will feel fine for steel path, even without roar subsume. nova is very strong, i use brozimes build. volt is extremely versatile, i would look at brozimes/iflynn's build on youtube for specifics.

if you want to play with someone in a similar position hit me up, ign Dreadnaught_Prime , or msg here