Do you guys think Tomlin or Sirianni get fired if they lose in the Playoffs?

Sirianni isn't going anywhere. Doesn't matter if they lose by 50. He's got a .704 winning percentage with them, highest of any active coach in the league and 5th highest all-time.

Tomlin I don't think goes anywhere. Steelers value stability too much. Unless he gets pressured to retire of course.
Considering he's only 52 years old and is probably looking to coach another 5-10 years, I don't see retirement as a realistic option and despite some Steelers fans getting anxious or unnerved about going one-and-done since Big Ben's retirement, well again, they don't have that franchise Pro Bowl QB and apparently some of those idiot fans think another HC will just waltz in there and get them one and they'll be appearing in SB's again. Or they assume that anyone could realistically coach those Steelers teams to the playoffs, which is another sign of how spoiled, and detached from reality many of them are having only 3 HC's in the past 55 years. Or just delusional.

If Tomlin gets "pressured" to retire, lets dispense with the formal BS and just call it what is is, being fired.

If Sirianni loses in the first round again, their might be some grumbling because Philly fans and sports talking heads can be very reactionary but his 2022 SB run has likely earned him maybe a few more seasons to rebuild and reconcentrate his teams and with Saquon appearing more likely to have several more outstanding seasons, the future is bright with him in Philly. I would be very surprised if Eagles did lose to Green Bay in the WC though anything could happen.