I feel you... I travel for work (at least until COVID) so once COVID is over I will have no choice but to eat out 5 days a week. I will not be able to cook at home. I haven't had surgery yet, but here are the strategies I'm planning: ordering plain grilled meat and fish with a side of steamed or roasted veggies (most nicer restaurants will let you order this way and I will bring a mini food scale that is about the size of a deck of cards with me - I already have it, or a measuring cup. I don't care who thinks I'm weird). For fast food, I will order a grilled chicken sandwich or egg, ham, and cheese breakfast sandwich and not eat the bread. I have heard a lot of people talking about P3 packs and I've eaten them before. I can just eat the cheese and nuts and skip the raisins or craisins. I can buy cheese sticks and packs of deli meat at grocery stores in most cities where I have access to a grocery store and a fridge in my hotel room.
I am not saying I will be perfect, but I know what the options are. You can eat healthy at restaurants. No, you don't know exactly what is in your food, but you can ask them not to add the butter/oil to your grilled meat or fish, you can say no to the bread, potatoes, rice, etc. And unless you're staying at a hotel with no fridge or microwave, you can take the food home for your next meal.
You got this! You may or may not be able to turn yourself into a gourmet cook, but either way, it is possible. My nutritionist felt like I could go back on the road after surgery and be successful, so I think you can too!