Can't really speak to your potential to compete - so much would depend on the makeup of other teams in your 12-teamer. But yes, I think you've got a solid squad... not "championship-level" in my eyes but competitive for sure.
That said, I'm not a huge fan of this deal for you - in terms of competing this year. Long-term, it's more palatable. It all comes down to who you're keeping with those 6 spots, in order to fairly assess. I'd currently guess your 6 keepers, in your set-up, as Hart, Stamkos, Rielly, Barkov, Couturier and either a 2nd G or Krug/Petry.
Looking at the deal:
Kreider/Palat - let's call it a wash.
Gibson/Bob - basically a wash for me too, although longer term I'd prefer to have Gibson over Bob (relevant if he's in your 6 keeps).
Krug/Sergachev - immediate production likely goes in favour of Krug, longer term, I'm fine with Sergachev and his upside as being as valuable.
Pick swap - clearly you upgrade here although 4-from-6 isn't massive. It's a sweetener.
Rielly/Hughes - Here's the meat of the deal. You're basically a 7F/4D start set-up, which for me, gives a LOT more value to D vs. F based on replacement options. 12 teams x 4D means 48 D in play vs 12 x 7F which is only 84F. Tons of value left on benches and/or waiver wire. With HIT/BLK the breadth of D who have value increase too though... so depending on your roster, if you've got enough scorers at F, you can still find value in D who don't score much but offer big peripherals. It's a strategy decision.
Both Rielly and Hughes should be a top 6 keeper moving forward, so no one is really being displaced (save maybe Krug if you kept him).
All that to say - this is close enough for me that the tie-breaker comes down to 2 things:
1) Knowing your league. You know how (in)active your league is. If you're confident you can swing trades when needed, by all means embrace some additional risk.
2) Who do you like most. If you're a huge fan of J.Hughes and believe he'll hit the lofty expectations - go for it. Same goes if you're big on Rielly though. Whoever you like more or happens to be "your" guy - have some fun and get him on your team.
tl:dr
This deal is a step sideways, not a huge win or loss in my eyes. If you want to compete THIS year, I likely hold. If you're more focused on the future, I likely pull the trigger. But either way, this doesn't max your chances for this year or crush your future... so don't overthink it.
Hope that long diatribe helped lol.