Did you skip searing it after sous vide? Did you sous vide it to the "instantly kill all bacteria" temperature (145°F for steak) thereby overcooking & destroying it, or did you sous vide to a lower temperature (at most 125°F) so that it'd reach a medium-rare 130°F-140°F after searing & carryover cooking during resting? It should have a nice seared crust, and the inside absolutely shouldn't be mushy.
Please research this. Done right, sous vide is amazing. But it is almost never the only technique used. Just like when you slow roast a prime rib at 200f, you MUST sear to get Maillard reaction and a satisfying texture.
At 90°C you can do sous vide, so basically use that waste heat entirely.
For such temperatures you'd need a CO2 heat pump, which is still expensive. I don't know about gas, as I don't even have a line to my place.