Unless you're walking on your hands, I'd lean towards it being primarily psychological. Part of your brain is probably thinking "OMFG I'm doing so much cardio, I'll never get gainz", but walking is rarely catabolic. I'm also still not seeing how walking would impair upper body recovery.
For sure, 2 hours five days a week is on the high side but if it's low intensity, it should become essentially a non-issue once your body adapts (one sign of your body having adapted is feet/legs feeling less tired at the end of the day). If you want to double-down, make sure you're eating something substantial on lunch break and don't sweat it.
Can I ask what you do for work? If we're talking, like, walking around a warehouse for two hours a day loading and unloading boxes of stuff, that's one thing and the walking itself wouldn't be the issue. If we're talking walking around a retail store to help customers, that's something else and not worth worrying about.