I’m a PPL and flight simmer, plus I was involved in a fixed base public sim operation so I know a great many airline fellas who used to come along to instruct sessions.
The truth is a lot of the GA crowd are very sniffy about MSFS so it’s probably best to keep your trap shut for now.
The truth is that flying the 777 on the desktop is pretty much an exercise in systems management, as it mostly is in real life. There ain’t much hand flying to do, plus a desktop sim is incredibly poor at replicating the feel of the real thing anyhow.
That said, all of the youngish guys I know who fly for the airlines now use the more advanced simulator aircraft (PMDG/Flight Sim Labs) etc to practice before they do sessions in the real sim. The desktop is incredibly good at the procedural/flow/drills stuff, but it’s not remotely flying in the way that you’ll be learning for your PPL.
I’d keep your sim flying and real world flying entirely apart as you will need the mental capacity to learn skills that you’ll find harder to attain than shooting a VNAV approach in the 777. Dodging weather, RT, navigation and LOOKING OUT OF THE WINDOW are all things that you’ll need to get good at and fast.
There’s absolutely no question that being proficient in the sim will help you down the line, especially if you can replicate your aircraft type, local area and landmarks as rightly posted earlier. MSFS 2020 with satellite ground scenery and landmarks is a game changer in this area. But first things first. Do more listening than talking and do what you’re taught. Good luck!