I would not spend significant amount of money on building an HT based on (IMO) shaky foundation of budget Polk speakers, That said I would advise to get a AVR which you could reuse later one then you have larger budget and rock 3.0 for now - it would still be an improvement over any soundbar
DENON AVR-X2000 7.1 Ch 4K Ultra HD Networking Receiver AirPlay | Accessories4less
For future: I would recommend you to save for new L/C/R and a separate budget for at-least $500 sub like SVS PB1000
At your budget I would look closely at two modified bookshelves and a matching center from Dennis Murphy:
Affordable Accuracy
Then use existing Polk for surround duty, where sound accuracy is not terribly important
p.s: Both Klipsch and Energy are owned and controlled by Audiovox, which have a reputation of using a good brand name to sell cheap crap.
They ruined more than one good brand using same methods - do some homework.